unknown 语法几道

憧憬

the teeth in the upper jaw function together those  in the lower jaw to cut ,tear and grind food

tom was selected president last semester , but he has since devoted   few of his spare time to his job.

答案是c d

大家觉得怎么改好呢

还有tribe做主语时是不是谓语动词要用复数？

waterfrog

第一题：together with

第二题：little

tribe我想和family地用法应该一样吧，看语境，有时候用单数，有时候用复数

三脚猫

我也不明白第二题的c has since devoted   是什么用法

leo1111

以下是引用pumpkin在2004-8-9 23:31:00的发言：

since

adv ==> at a time in the past after a particular time or event.

I have since fortten what our argument was about.

He walked out of the office last Tuesday and no one has seen him since.

同意