Lesson 2- Whether / If

Whether / If

Both whether and if are used to introduce a yes/no
question:

Examples:

He asked me whether I felt well.

We're not sure if they have decided.

The verb discuss generally takes whether rather than if.

Examples:

We discussed whether he should be hired.

They discussed whether to invest in the new idea.

After Prepositions

Use only whether after prepositions:

Examples:

We talked about whether we should go or not.

I looked into whether he should stay.

Infinitives

Use only whether before infinitives:

Examples:

She can't decide whether to buy the house or wait.

He considered whether to give up the position or quit next year.

Formal / Informal

Generally, whether is considered more formal than if.

Examples:

Let me know whether you will be able to attend the conference.

The CEO will decide whether this is a risk worth taking.


Source from http://esl.about.com/od/grammarintermediate/a/cm_wif.htm