③Be sure to call(call) us and let us know you've got back safely.

　　一定要给我们打电话，让我们知道你已经平安返回。

　　(2) up to 直到；多达；由......决定；忙于，从事；胜任

　　　写出下列句中up to的含义

　　④ Up to three students were late for class today, which made my teacher very angry.

　　⑤It's up to you whether we accept the present or not.

　　⑥We all agree that he is up to the position.

　　⑦Some people believe those men are spies，but no one knows what they are up to.

　　【答案】　④高达；多达　⑤由......决定　⑥胜任　⑦忙于；做

　　(1)be up to (doing sth.) 打算做/正在做(不好的事)；胜任(做某事)

　　(2)It's up to you. (交际用语)由你决定。

　　It's up to sb.to do sth. 由某人决定做某事

　　up to now 直到现在(常与现在完成时连用)

　　⑧It's up to you to decide (decide)whether to go or not.由你决定走还是不走。

　　⑨－Shall we go out for dinner or eat at home?

　　--我们是出去吃饭还是在家吃呢？

　　－It's up to you．

　　--由你决定。

　　 make efforts 作出努力

　　(教材P12)The report shows that we are making some progress but that we need to make greater efforts.报告显示：我们正在进步，但是我们必须作出更大的努力。

　　(1) make efforts/an effort/every effort to do sth.

　　 尽一切努力做某事

　　spare no effort(to do) 不遗余力

(2)without effort 容易地，不费力地