If/Whether usage. "It is doubtful whether he is telling the truth"
74426
"Whether" Vs. "If"
34087
Should I use "could" or "would" in the following case?
93559
use "if" rather than "whether" when the object clause is negative?
150084
Use "or" or "nor"?
111575
What does this if-then statement mean?
155326
How to handle con­di­tional clauses where it’s un­known whether the pro­ta­sis’s con­di­tion ac­tu­ally got ful­filled or not?
123682
Can I use an "if" clause without "then"?
104867
Ambiguity of the word 'any'?
142048
Conditionals (Past Tense)
95851
Validity of an argument with a contradictory conclusion
108316
Why is "He said me he was ..." ungrammatical, but "He told me he was ..." is not?
85899
Should I say "what does it means" or "what does it mean"?
20462
Validity of conditional statement when the premise is false.
46644
Was or is? Confusion
52403
Need help understanding phrases of the form "x if y"
94820
How to use 'would' to express vagueness
43336
Question sentences involving negation