按电话闭塞法行车，防护信号机故障时，应如何办理发车作业？

There seems something wrong with my bike.I would like to get it________.[ ]

A．repair  

B．to repair

C．repairing  

D．repaired

从10个外观完全相同的产品中，任意抽取1个产品进行检测，抽到不合格产品的概率是0.2，则这10个产品中不合格的产品有______个．

Nine in ten parents said there were significant differences in their approach to educating their

children compared with ____ of their parents.

 [ ]

A. those

B. one

C. both

D. that

有关尿干化学检测原理，葡萄糖测定用（）

A．偶氮偶联法 

B．马来酐试剂 

C．葡萄糖氧化酶法 

D．多聚电解质离子解离法 

E．特异性酯酶法

一定质量的理想气体经历某过程后，它的体积和压强都减小了，则气体对外______。

A．一定做负功，热力学能一定增加
B．一定做负功，热力学能一定减小
C．不一定做负功，热力学能一定增加
D．不一定做负功，热力学能一定减小