________ there are living creatures in the outer space as those on Earth hasn't been proved until now.
A．How B．When
C．Where D．Whether
We haven't settled the problem of ________ it is necessary for him to study abroad.
A．why B．whether
C．what D．how
It surprised us all ________ Kate made such big progress in this final exam.
A．when B．that
C．how D．whether
________ some teenagers don't realize is ________ difficult life can be after they get addicted to drugs.
A．What; what a B．That; how
C．What; how D．That; what
_______ didn't attend the lecture yesterday won't be given full marks.
A．Any one B．Whoever
C．Who D．The person
It could be learned from the teacher's eyes ________ he was very satisfied with her performance.
A．that B．whether
C．what D．where
