已知圆$C$的极坐标方程为$\rho =a\sin \theta$，则“$a=2$”是“圆$C$与极轴所在直线相切”的  （    ）

以下天体系统中，不包含地球的是（  ）

阅读对话，判断正误。

    Pedro: Hi, Li Lei. When do you start class in the morning?

    Li Mei: Usually at 8 o'clock.

   Pedro: It’s early. In Spain we start class at 9 o'clock.

   Li Mei: When do you usually eat dinner, Pedro?

   Pedro: At 9:30 or 10:00 p.m.

   Li Mei: Wow! That's too late. I always go to bed at 9:30. What do you do on the weekend?

   Pedro: I often play football with my friends. Sometimes I go shopping with my mum.

   Li Mei: Sounds interesting. I usually wash my clothes and clean my room at home.

指出下列各句运用的描写方法。

①他身材很高大；青白脸色，皱纹间时常夹些伤痕；一部乱蓬蓬的花白的胡子。____

②有一回对我说道，“你读过书么？”____

③孔乙己显出极高兴的样子，将两个指头的长指甲敲着柜台，点头说，“对呀对呀！……回字有四样写法，你知道么？”____

2013年12月，“玉兔号”月球车在月球上软着陆成功，如图所示，下列关于月球车在月球上的说法正确的是（　　）