TXA2减少常见于（） A.血栓前状态 B.糖尿病 C.心肌梗死 D.脑血栓形成 E

用所给词的适当形式填空。

       What do you think of watching TV? I don't think it is good for students. First, children       1        (be) different from adults. It's true that students like       2       (relax) by watching TV. However, the dangerous thing is that they can't take their eyes off the screen. They will go on watching TV for hours and hours. It's bad for their eyes.      3      (two), many students have the habit of     4     (watch) too much TV. Then they will have little time for sports. Third, some TV programs are not     5    (suit) for students. Some even lead them to comes, which I think is a terrible thing.

内燃机的故障和失效分析是( )的核心问题。

A．可靠性

B．经济性

C．安全性

D．效益性

保管活水产品的目的在于使之不死或少死，这主要取决于水中的（）。

征税客体为实物时一般实行从量计征，即采取下列哪种税率形式______。

A．比例税率
B．全额累进税率
C．超额累进税率
D．定额税率

分析碑志在历史研究中的价值以及石经在校勘中的作用。