1 . 北京时间10月30日4时27分，我国搭载神舟十九号载人飞船的长征二号F遥十九运载火箭在酒泉卫星发射中心点火发射．4时45分左右，神舟十九号载人飞船与火箭成功分离进入预定轨道，发射取得圆满成功．据不完全统计，仅微博观看人数就达到了约756万人．数字7560000用科学记数法可以表示为____．

2 . — Can you come to my party this evening?
— Sorry, I can’t. I have to prepare ________ my exams.

A．of

B．for

C．about

D．with

3 . That is his ________ (办公室). He plans his lessons there.

4 . Look at the ________ (标志). We can’t swim here. It’s dangerous.

5 . This is Tom’s fishing rod.（对画线部分提问）
________ fishing rod ________ this?

6 . 这个发夹多漂亮啊！
________ the ________ is!

7 . How many girl students are there in the class?

A．21.

B．24.

C．42.

8 . Jack is clever. He can ________ (计算出) these maths problems.

9 . 图书馆在我们教学楼的前面。
The library is ________ ________ ________ our teaching building.

10 . 某产品原价a元，提价10%后又降价了10%，则现在的价格是（        ）

A．0.9a

B．1.1a

C．a

D．0.99a