- (Complement) - The question is if the man can be trusted. - Correct but less preferred. If an indirect question is fronted , whether is used... - Whether I'll have time I'm not sure at[r]
(1)Whether and If
http://gmat-grammar.blogspot.com/2006/07/whether-vs-if.html
1) After Prepositions, we use only whether
- I haven't settled the question of whether I'll go back home
- There was a big argument about whether we should move to a new house 2) Whether, but not if, is used before infinitives
- They can't decide whether to get married now or wait
3) When a question-word clause is a subject or complement, whether is preferred - Whether we can stay with my mother is another matter - (Subject)
- The question is whether the man can be trusted - (Complement) - The question is if the man can be trusted - Correct but less preferred 4) If an indirect question is fronted , whether is used
- Whether I'll have time I'm not sure at the moment
5) Whether is generally preferred in a two - part question with or
- The Directors have not decided whether they will recommend a dividend or reinvest the profits 6) After verbs that are more common in a formal style, whether is preferred
- We discussed whether we should close the shop 7) Whether and if both can introduce indirect questions - I'm not sure whether / if I'll have time
8) Yes / No questions are reported with if or whether - I don't know if / whether I can help you
Note - The word IF does not always signal a conditional sentence In such cases, the GMAT prefers "whether" instead of "if"
http://gmat-grammar.blogspot.com/2006/07/whether-vs-if.html fronted