Mark Twain _____ along the Mississippi River, which was _____ to his writing.

A．was grown up / benefit

B．brought up / benefit

C．grew up / of beneficial

D．was brought up / beneficial

设x和y均为bool 量，则x＆＆y为真的条件是______ 。

A．其中一个为假

B．其中一个为真

C．二者均为假

D．二者均为真