美国加入一战的时间是（   ）

阅读下面的对话完成任务。

A: Excuse me, Susan. （1）Is this your backpack?

B: No, it isn't. It's Jack's. （2）My backpack is green.

A: Is your computer game in the lost and found case?

B: No, it's Jack's. And that white eraser is Jack's, too.

A: Do you know Jack?

B: Yes, I do. （3）他是一个英国男孩。He's in Class One, Grade Seven.

A: Oh, what's his telephone number?

B: 100-2116

A: Is Miss Miller his English teacher?

B: Yes, you're right.

第四届全国非公有制经济人士表彰大会于 2014 年 11 月在北京举行。我国重视发展非公有制经济，是因为它有利于（     ）

①繁荣城乡经济②扩大社会就业 ③缩小贫富差距 ④增强经济活力