卵巢肿瘤蒂扭转的主要症状是
A．急性腹痛
B．发热
C．恶心、呕吐
D．白细胞数升高
E．休克
参考答案：A
Everyone is supposed ____ a seat belt in the car.[ ]
A. wearing
B. to wear
C. to be worn
D. wears
天然气探测模块对低报警在爆炸下限（）作出显示
A、0%
B、20%
C、60%
D、80%
