生活要自立，人生当自强。自强不息的人会在生活中表现出如下的一些特征（） ①在困难

The passage suggests that ______.

A．one's intelligence is born by nature

B．people can be trained to make best use of their mental abilities

C．IQ tests are totally unreliable

D．most psychologists are in favor of the idea of "self-efficacy"

人字桅杆和独脚桅杆应选用优质钢、木材料制作；人字桅杆两腿的夹角不得大于（）。

A.30°

B.40°

C.45°

D.50°

流量

什么是分解住院？