《南京条约》签订后，英、美等西方资本主义国家像潮水一般涌进来的西方工业产品，在中国市场上得不到广泛的销路，英国下院一个调查中英贸易状况的报告承认：近来同这个国家的贸易处于十分不能令人满意的状态。上述现象出现的原因是（    ）

There are lots of rules at Selina's school.
She agrees with some1them. For example, they can't arrive2 , they can't  run in the hallways, and they can't eat in class. All3 rules are okay because they're reasonable(合情合理的).
But there are some rules Selina4agree with. For example, at her school they have to wear a uniform and they can't wear jeans. But she thinks jeans are5because they're comfortable. In school, they can't listen to music in art class. Selina doesn't agree with this rule. She thinks 6 music in art crass is okay.
Selina7 has to follow some rules at home. For example,8she wants towatch TV, she has to finish her homework first. And she can't go out with her friends 9school nights, that is, from Monday to Friday, she also has to clean her room10week. Luckily, she doesn't have to take out the trash（垃圾）. She hates it.

图中直角的个数为（     ）个。

如图所示，线圈两端与电阻相连构成闭合回路，在线圈上方有一竖直放置的条形磁铁，磁铁的S极朝下。在将磁铁的S极插入线圈的过程中

下列方程中，常数项为零的是（  ）