急性心包炎在我国最常见的病因是（） A.结核性 B.风湿性 C.非特异性 D.化脓性

At the beginning ofleaming English,  I had a lot of trouble _____with other people in it.                     [ ]

A. communicate                      

B. to communicate              

C. communicating

下列纠纷中不能仲裁的有()

A．房地产纠纷

B．收养纠纷

C．涉外商事纠纷

D．技术服务合同纠纷

（）

A．

B．

C．

D．

For them, it was very difficult to __________ the town from the hand of the enemy.[ ]

A. win out  

B. win over

C. win back  

D. win through

电梯的维护保养应当由（）或者依照本法取得许可的安装、改造、修理单位进行。

A.电梯制造单位

B.电梯使用单位

C.上级主管部门