Learn English – How about going to the cinema tonight

All full questions* require a finite auxiliary verb^† (that is, an auxiliary verb tensed for either past or present) before the subject. When the verb in the sentence is a construction with an auxiliary, this is accomplished by switching the subject and the auxiliary. When the verb is a lexical verb with no auxiliary, it is accomplished with DO-support: the tense is removed from the verb and put on a form of DO before the subject:

He is John Smith. → Is he John Smith?
He is [who]. → Who is he?

He has gone to town. → Has he gone to town?
He has gone [where]. → Where has he gone?

You look like an executive. → Do you look like an executive?
You look like [what]. → What do you look like?

Your second sentence, however, confuses two different constructions. There What is not an interrogative, a question word, but a relative pronoun heading a clause which acts as a noun phrase. The statement form would be:

[_Subject What you said] [_Verb turned out] [_Complement to be true].

Consequently, the question form would be:

Did what you said turn out to be true?

* As Peter Flom points out, questions may be truncated very substantially in discourse context.
^† BE is always considered an auxiliary, even when it is the only verb.

Whether is not a question word, although it looks like one.

Question words beginning with wh are the following:

• what
• which
• where
• who
• whose
• when
• why

The rule for making questions using question words is fairly simple:

Question word + auxiliary + subject + infinite or, "QUASI" is a useful acronym. ^{(It is not infallible but it works most of the time)}

1) Which colour did she choose to make it? Blue or green? (if there is a limited choice)

2) What colours did she use? (a wider choice of colours is inferred here)

3) Who made it? Did you? OR "Was it me or you?" (in this case, who is the subject of the question and does not require an auxiliary)

You can omit the wh question word and ask a yes/no type question.

Auxiliary + subject + infinite

• "Did you use blue or green?" asked Maria.
• Maria asked, "Did you make it?"

If you wanted to use whether you have to rephrase your sentence. Note that the following are not questions. There is no question mark at the end.

• Maria asked whether she used blue or green.
• Maria asked whether [name] made it or not.

If you really need to make questions with whether then the following is acceptable

• Do you know whether she used blue or green to make her scarf (it)?
• Did you find out whether it was me or her who made it?