wǒ jīntiān qù tǐjiǎn, shìlì hěn hǎo.

In Mandarin, time words usually come before the verb phrase. So 我今天去体检 follows a very common pattern:

subject + time + verb + object

Here:

• 我 = subject
• 今天 = time
• 去体检 = verb phrase

You can also say 今天我去体检, which is also natural. The difference is mainly emphasis:

• 我今天去体检 = more neutral
• 今天我去体检 = puts a little more focus on today

Chinese verbs do not automatically show tense the way English verbs do. Very often, you understand the time from context.

So 我今天去体检 could mean:

• I’m going for a physical today
• I went for a physical today

In this full sentence, the second clause 视力很好 suggests the exam has already happened, because the speaker already knows the result. So the most natural interpretation is something like I went for a physical today, and my eyesight is good.

If you want to make completion clearer, you could say:

• 我今天去体检了，视力很好。

It can function as both, depending on the sentence.

• As a noun, 体检 means a physical exam / medical checkup
• In everyday speech, it is also commonly used like a verb meaning to get a physical

So 去体检 literally means go do a physical exam, or more naturally, go for a checkup.

You may also hear:

• 做体检 = have a physical
• 去做体检 = go have a physical

All of these are common.

Chinese often connects related ideas just by putting clauses next to each other, often with a comma. This is very normal in Chinese writing.

So:

• 我今天去体检，视力很好。

works like:

• I went for a physical today, and my eyesight is good.

Chinese does not always need an explicit connector like and, so, or because when the relationship is clear from context.

If you want, you could make the link more explicit, for example:

• 我今天去体检，结果视力很好。
  I went for a physical today, and the result was that my eyesight is good.

But the original sentence is shorter and natural.

This is a very common question. In sentences like this, 很 often does not mean a strong very. It often acts more like a neutral linker before an adjective.

So:

• 视力很好 often just means the eyesight is good
• not necessarily the eyesight is very good

Mandarin usually does not like a bare adjective as the whole predicate in a simple statement unless there is contrast or comparison. So 很 is often added naturally.

Compare:

• 视力好 = can sound more contrastive, like the eyesight is good (as opposed to something else)
• 视力很好 = a normal, smooth statement

If you really want to emphasize very, you can use:

• 非常好
• 特别好

Because 好 is an adjective, not a noun.

In Mandarin:

• 是 is mainly used to connect a subject with a noun phrase
• adjectives can usually act as the predicate by themselves

So:

• 他是老师。 = He is a teacher.
• 他很好。 = He is good / He is fine.

Not:

• 他是好 ✘

That is why 视力很好 is correct, while 视力是很好 would only work in special emphatic contexts, not as the basic sentence.

Because Chinese often leaves out information that is already obvious from context.

After 我今天去体检, it is clear that 视力 refers to my eyesight, so 我的 can be omitted.

So:

• 视力很好 = [my] eyesight is good
• 我的视力很好 = also correct, but more explicit

Adding 我的 may sound more natural if you want emphasis or contrast:

• 我的视力很好，他的视力不太好。
  My eyesight is good; his isn’t very good.

Not exactly.

视力 means eyesight or visual acuity—how well you can see.

It does not mean the physical eyes themselves. For that, you would use:

• 眼睛 = eyes

So:

• 视力很好 = eyesight is good
• 眼睛很好 is less natural if you mean visual ability; it sounds more like saying the eyes themselves are healthy or fine

If you specifically mean eye health, you might say:

• 眼睛很健康
• 眼睛没问题

Yes. Those are both natural.

Common versions include:

• 我今天去体检。
• 我今天做体检。
• 我今天去做体检。

The differences are small:

• 去体检 = go for a physical
• 做体检 = have a physical
• 去做体检 = go and have a physical

In everyday conversation, all three can work. The original sentence is concise and natural.

Yes. There are some third-tone sandhi effects.

Two common places are:

• 体检: tǐ jiǎn → the first third tone is pronounced more like a rising tone in connected speech
• 很好: hěn hǎo → hěn changes in pronunciation to a rising tone before another third tone

So although the dictionary tones are:

• 体 = 3rd tone
• 检 = 3rd tone
• 很 = 3rd tone
• 好 = 3rd tone

in natural speech, the first of each pair is usually pronounced like a 2nd tone.

Learners often hear:

• tíjiǎn
• hénhǎo

But the written tone marks stay the same.

Often, yes—especially if you want to emphasize that the checkup already happened.

Compare:

• 我今天去体检，视力很好。
• 我今天去体检了，视力很好。

The version with 了 makes the completed action more explicit. The version without 了 is still understandable, especially when the second clause already shows that the exam result is known.

So the original sentence is fine, but in real conversation many speakers might prefer:

• 我今天去体检了，视力很好。

if they are clearly talking about something they already did.