1 . No one knows _______ he really is — except that he's known by the name "Jan Thorburn".

2 . 是我们的父母愿意尽他们所能来帮助我们。
________ ________ our parents ________ are willing to do whatever they can to help us.

3 . ________will be in charge of the company is a mystery.

A．It

B．Whom

C．Who

D．Whoever

4 . ______ is reported, the number of female smokers in UK, has increased by 5% in the past 5 years.

A．Which

B．Who

C．What

D．As