I go to school by _______, but my best friend goes there ______foot.

A．a bike; by

B．bikes; on

C．bike; on

D．bike; by

There is _____ boat in ________river.
A. a; the                B. the; a                C. a; a

        you go,           you do, I will be right here waiting for you.
A. Wherever; whatever  B. If ; if           C. Where; what