（ ） I cannot understand is （ ） she wants to resign her present job.
（A）What; why
（B）Which; how
（C）That; why
（D）What; which
It is not immediately clear （ ） the financial crisis will soon be over.
（A）since
（B）what
（C）when
（D）whether
It suddenly occurred to him （ ） he had left his keys in the office.
（A）whether
（B）where
（C）which
（D）that
