Sequence of tenses

[svetik]

Which forms of the verbs in brackets must be used in the following sentence?

Provided the dam (build) by February, the flood (strike) several towns.

Thank you

[2006]

Which forms of the verbs in brackets must be used in the following sentence?

Provided the dam (build) by February, the flood (strike) several towns.

Thank you

Tell us what you think.

[Linguist__]

Which forms of the verbs in brackets must be used in the following sentence?

Provided the dam (build) by February, the flood (strike) several towns.

Thank you

(Not a teacher)

I can't really understand this. I would have thought the dam being built would prevent a flood? With that in mind, I would say:

"Provided the dam is built by February, the flood will not strike several towns."

Although, such a sentence could be completely changed, so that it is, " Provded the dam is built by February, the flooding of several towns will be avoided." So I don't know if my understanding of the sentence is correct.

[svetik]

Tell us what you think.

I'm not sure. It's supposed to be a conditional sentence. So, we cannot use the Future in this part. By February shows that the actiond will have to be completed by the certain time in the Future.
Can we use the present perfect the first part of the sentence?
Provided the dam has not been built by February, the flood will strike several towns.

[svetik]

(Not a teacher)

I can't really understand this. I would have thought the dam being built would prevent a flood? With that in mind, I would say:

"Provided the dam is built by February, the flood will not strike several towns."

Although, such a sentence could be completely changed, so that it is, " Provded the dam is built by February, the flooding of several towns will be avoided." So I don't know if my understanding of the sentence is correct.

The meaning is that if the dam is not going to be built by February, the flood will strike several towns.
I need to show the sequence of tenses in this sentence. First, the dam will be built and this will prevent towns from flood after.

[Raymott]

The meaning is that if the dam is not going to be built by February, the flood will strike several towns.
I need to show the sequence of tenses in this sentence. First, the dam will be built and this will prevent towns from flood after.

Then "provided" is not the right word. You need something like:
Unless the dam is built by February, the flood will strike several towns.

The sentence you've given makes some sense grammatically:
Provided the dam has not been built by February, the flood will strike several towns.
But we wouldn't express it this way in English - unless the second clause was something positive, as in:
Provided we don't run out of gas, we should reach town by 6pm.
NOT
*Provided we stay above 100 miles per hour, the police should stop and book us.
This last sentence, as well as yours, suggest that we want the police to book us, or the towns to be flooded.