zhège tàocān yìfāngmiàn dàikuān dà, yìfāngmiàn yuèzūfèi bǐjiào piányi.

It links two different positive (or contrasting) aspects of the same thing.

In this sentence:

• 一方面带宽大
• 一方面月租费比较便宜

it means something like:

• on the one hand, the bandwidth is large
• on the other hand, the monthly fee is relatively cheap

A very natural English translation is often just:

• This plan has high bandwidth, and at the same time the monthly fee is relatively low.

So 一方面……一方面…… is not always a strong contrast like English however. It can simply mean in one respect... and in another respect....

This is because of the tone change rule for 一.

Normally 一 is first tone: yī.
But in actual speech, its tone often changes depending on the tone of the next syllable:

• before a 4th-tone syllable, 一 becomes yí
• before a 1st, 2nd, or 3rd-tone syllable, 一 becomes yì

Here, 方 is fāng (1st tone), so 一方面 is pronounced yìfāngmiàn.

So the written character stays 一, but the pronunciation changes.

Because in Chinese, adjectives can act as predicates by themselves.

So:

• 带宽大 = the bandwidth is large / high
• 月租费比较便宜 = the monthly fee is relatively cheap

You do not normally say:

• 带宽是大
• 月租费是便宜

Those sound unnatural in standard Mandarin.

This is a very common difference from English. In English, you usually need to be. In Chinese, an adjective often works directly as the predicate.

Learners often learn patterns like:

• 他很高
• 这个很贵

so they may expect 很 before adjectives. But 很 is not required in every sentence.

Here, 大 appears naturally without 很 because the sentence already has a clear structure of contrast/listing:

• 一方面带宽大，一方面月租费比较便宜

This kind of structure makes the statement sound complete.

If you said 带宽很大, that would also be possible in some contexts, but the original sentence is already perfectly natural.

So the short version is:

• Adjective alone is often fine in structured or contrastive sentences.
• 很 is common, but not mandatory.

In Chinese, 大 is often used for things that are conceptually large, strong, broad, or high in capacity.

So 带宽大 means:

• the bandwidth is large
• more naturally in English: the bandwidth is high or it offers a lot of bandwidth

English and Chinese do not always match word-for-word with adjectives.
Chinese says big/large bandwidth, while English often prefers high bandwidth.

So 大 here is completely normal.

They are related, but they are not the same word.

• 带宽 = bandwidth
• 宽带 = broadband

So in this sentence, 带宽大 means the bandwidth is high, not the broadband is big.

This is a common point of confusion because the same two characters appear in reverse order.

比较 often means relatively or fairly.

So:

• 月租费比较便宜 = the monthly fee is relatively cheap

Yes, it usually suggests some kind of comparison, even if the comparison target is not stated explicitly. The unstated idea might be:

• compared with other plans
• compared with what you would expect
• compared with similar services

It is softer than simply saying:

• 月租费便宜 = the monthly fee is cheap

Using 比较 makes the statement sound a little more moderate and natural.

Because 比较 here modifies the adjective 便宜, not the noun 月租费.

The structure is:

• 月租费 = the monthly fee
• 比较便宜 = relatively cheap

So together:

• 月租费比较便宜 = the monthly fee is relatively cheap

If you moved 比较 before the noun, it would sound wrong in this sentence.

A helpful way to remember it is:

• noun + predicate/adjective phrase

So:

• 房子比较贵
• 这个菜比较好吃
• 月租费比较便宜

No. 套餐 originally often refers to a set meal or combo meal, but it is also widely used for service packages/plans.

In this sentence, 这个套餐 means:

• this package
• this plan

For things like:

• phone plans
• internet plans
• streaming bundles
• data packages

套餐 is very common.

So here it definitely does not mean a food combo.

这个 means this and points to a specific plan.

• 这个套餐 = this plan/package

If you just say 套餐, it becomes more general:

• 套餐一方面带宽大…… sounds more like the plan / a plan has...

Using 这个 makes it clear you are talking about this particular package, probably one already being discussed or shown.

They are similar, but not always identical in nuance.

• 月费 = monthly fee/monthly charge
• 月租费 = monthly rental fee / monthly subscription-like fee

In many telecom or internet contexts, 月租费 is commonly used for the recurring monthly amount you pay.

In everyday conversation, people may sometimes use 月费 more casually, but 月租费 sounds a bit more specific to service charges like phone/internet plans.

Yes, in natural English you might translate the whole idea more freely that way.

A direct translation is closer to:

• This plan, on the one hand, has high bandwidth; on the other hand, its monthly fee is relatively cheap.

But a more natural English version could be:

• This plan is good because it offers high bandwidth and the monthly fee is relatively low.

So if the goal is understanding the Chinese, it helps to know that the Chinese sentence is listing two advantages.

The comma separates the two 一方面 clauses:

• 一方面带宽大，
• 一方面月租费比较便宜。

This makes the parallel structure easy to read.

Chinese punctuation is very important for showing structure, especially in patterns like:

• 一方面……，一方面……
• 虽然……，但是……
• 因为……，所以……

So the comma here is the normal and expected punctuation.

Sometimes yes, but it changes the feel slightly.

You may hear both:

• 一方面……一方面……
• 一方面……另一方面……

Both can work.

Very roughly:

• 一方面……一方面…… feels more symmetrical
• 一方面……另一方面…… can feel a little more like on one hand... on the other hand...

In this sentence, the original 一方面……一方面…… is completely natural because it is presenting two advantages in parallel.

It is fairly neutral and natural, especially in contexts like:

• product descriptions
• sales talk
• customer service
• online reviews
• advertisements

Words like 套餐, 带宽, and 月租费 give it a somewhat practical, commercial tone, but the grammar itself is very common and useful in everyday Mandarin.