zhège rènwu hěn zhòngyào.

个 is a measure word (also called a classifier).

In Mandarin, when you say this + noun or that + noun, you usually need a measure word between them:

• 这 + 个 + 任务
• 那 + 个 + 人
• 这 + 本 + 书

So 这个任务 literally looks like:

• 这 = this
• 个 = a general measure word
• 任务 = task / mission

For many nouns, 个 is the most common general classifier, and it works fine here.

In standard Mandarin, the usual form is 这个任务.

Sometimes in casual speech, especially in some regional styles, people may drop the measure word and say something like 这任务, but learners should generally use 这个任务 because it is the safest and most standard choice.

So for now, treat 这个任务 as the normal pattern.

Not necessarily.

In Mandarin, when an adjective acts as the predicate of a sentence, 很 is often used even when the meaning is just plain descriptive, not strongly emphatic.

So:

• 这个任务很重要。 usually means This task is important.

It does not always mean This task is very important in a strong emotional sense.

If you want to make it clearly more emphatic, you could say:

• 这个任务非常重要。 = This task is very important.
• 这个任务特别重要。 = This task is especially important.

A useful beginner rule is:

• Noun + 很 + adjective often sounds natural for simple description.

Yes, but it depends on context.

这个任务重要 is grammatically possible, but it often sounds more contrastive, emphatic, or like you are making a stronger judgment in context.

For example, it might sound like:

• This task is important (as opposed to some other task)
• This task matters

For neutral everyday description, 这个任务很重要 is usually the most natural.

重要 is an adjective meaning important.

In Mandarin, adjectives can often function directly as predicates, so you do not need a separate word for is the way you do in English.

English:

• This task is important.

Chinese:

• 这个任务很重要。

There is no 是 here because important is an adjective, not a noun.

Because 是 is usually used to link a subject with a noun phrase, not with an adjective in this kind of sentence.

Compare:

• 这是任务。 = This is a task.
  (是 links to a noun)

• 这个任务很重要。 = This task is important.
  (重要 is an adjective, so 是 is normally not used)

If you say 这个任务是重要, that sounds unnatural in ordinary Mandarin.

In normal speech, 这个 is usually pronounced zhè ge, with:

• 这 = fourth tone
• 个 = often a neutral tone here

So it sounds lighter than a full gè.

Although dictionaries may show the full tone of 个 when it stands alone, in 这个, the second syllable is very commonly neutral in natural speech.

Because the second syllable wu in 任务 is commonly pronounced with a neutral tone in standard speech.

So:

• 任 = fourth tone: rèn
• 务 = often neutral tone here: wu

This is common in many two-syllable Mandarin words, where the second syllable becomes lighter.

In this word, it is zhòngyào.

• 重 can have more than one pronunciation in Chinese.
• In 重要 meaning important, it is zhòng.

So:

• 重 = fourth tone: zhòng
• 要 = fourth tone: yào

Be careful not to read it as chóngyào, which would be incorrect here.

The structure is:

• 这个任务 = topic/subject: this task
• 很重要 = predicate: is important

So the pattern is:

• Subject + 很 + Adjective

This is a very common Mandarin sentence pattern, for example:

• 这本书很有意思。 = This book is interesting.
• 那个地方很漂亮。 = That place is beautiful.
• 今天很忙。 = Today is busy / I’m busy today.

Often yes, but its range can be a little broader depending on context.

任务 can mean:

• task
• assignment
• mission

It is often used for something that has a clear goal, duty, or responsibility attached to it.

So 这个任务很重要 could fit many situations, such as:

• a work assignment
• a school task
• a project duty
• an official mission

Yes. 这个任务很重要。 is neutral and natural in both spoken and written Mandarin.

It works well in:

• everyday conversation
• classroom language
• workplace discussions
• written instructions or reports

If you wanted to sound more formal or forceful, you might choose a stronger word such as:

• 这个任务非常重要。
• 这项任务十分重要。

But the original sentence is already completely normal and appropriate.