动物界中最高等的动物类群是（    ）

下列各句中画横线成语的使用,全都正确的一项是（    ）

①第二展厅的文物如同一部浓缩的史书，举重若轻地展示了先民们在恶劣的自然条件下顽强战争、繁衍生息的漫长历史。

②这部翻译小说虽然是以家庭生活为题材的，却多侧面、多视角地展现出那个时代光怪陆离的社会生活画卷。

③毕业后他的同学大都顺理成章地走上了音乐创作之路，而他却改换门庭，另有所爱，一头扎进中国古代文化研究中。

④就对后世的影响来说，我们一致认为《封神演义》虽然比不上《西游记》，但和《聊斋志异》是可以并行不悖的。

⑤在那几年的工作学习中，杨老师给了我很大的帮助，他的教导在我听来如同空谷足音，给我启示，带我走出困惑。

⑥这个人在就职演说时信誓旦旦，表示决不辜负大家的期望，可是一登上官位，就经不起利欲的诱惑了。

阅读理解                                                           

                                                                Table manners in America

        Don't circle your plate with your arms. If you do so, you will become the focus  (焦点)  of the table. Everyone would wonder, "Is there anything wrong with the food?" This may give a wrong message that you don't like the food or something like that.

       Don't push the plate back when finished. Leave it where it was. Do you want to let the hostess (女主人)(1)_________(know ) that you've just done a labours。

        Don't lean (倚靠) back and say "I'm through" or "I'm full". Just put the fork and knife across the plate. That's all. 

       (2)Don't cut up everything before you start to eat. Cut only one or two bites (块) at a time. Never take a huge mouthful of anything. Do you want to show how hungry you are? Don't do that. It's not so good.

        It's never good to reach across the table for anything. If the thing you want is not at hand, simply ask the nearest person for help, like "(3) Mrs. Smith, could you pass me the dish?"

有一质量为540g，体积为300cm³的空心铝球（ρ_铝=2.7×10⁷kg/m³），若空心部分装满水，总质量为____g。

在光滑的水平地面上，有两个静止的物体A和B，它们的质量分别m和3m．当它们同时受到相同的水平力F作用相等的一段时间后，下列说法正确的是（　　）