Tom has gone out. Tom _______. A. was out B. has been out C. is off D. will be out 说明:对不起,由于匆忙,原题中的 C选项打成了 is out,其实是is off, 很抱歉!另外,我说请专家再补充的意思没说清楚,我...
It can loosely be described as travel that takes place at regular intervals-often in an annual cycle-that may involve many members of a species, and is rewarded onl...