Which structure is not correct?

[Mehrgan]

Hi all,
Could anyone please tell me if any of the following sentences is not a normal way of saying what is meant?


1. One thing you need to do is, choose the right dictionary and...
2. One thing you need to do is, to choose the right dictionary and...
3. One thing you need to do is, choosing the right dictionary and...




Thanks a lot in advance.

[5jj]

1. One thing you need to do is choose the right dictionary and...
2. One thing you need to do is to choose the right dictionary and...
3. One thing you need to do is choosing the right dictionary and...

No commas,
The first two are fine; I prefer #1. #3 is incorrect.

[freezeframe]

Hi all,
Could anyone please tell me if any of the following sentences is not a normal way of saying what is meant?


1. One thing you need to do is, choose the right dictionary and...
2. One thing you need to do is, to choose the right dictionary and...
3. One thing you need to do is, choosing the right dictionary and...




Thanks a lot in advance.

3 is not "normal".

Also, you don't need a comma.

Also, if this is the only thing they need to do, you need to say "The one thing". The way you have it written, I expect it to continue: "another thing you need to do is actually use it..."

[Mehrgan]

No commas,
The first two are fine; I prefer #1. #3 is incorrect.

Thnaks. How about the following sentence?

Choosing the right dictionary is one/another thing you need to do.

If it's correct, then would you please explain how the third example in my previous post is not correct? I used to think the third example was a case of gerunds.

[5jj]

Thnaks. How about the following sentence?

Choosing the right dictionary is one/another thing you need to do.

If it's correct, then would you please explain how the third example in my previous post is not correct? I used to think the third example was a case of gerunds.

3. One thing you need to do is choosing/(to) choose the right dictionary and...
You need choosing/to choose...

3a. One thing you need to think about is choosing/to choose the...
You think about choosing/to choose...