半通行地沟内,管道或保温层外表面至沟顶的净距的取值范围为()。
A.50~100mm
B.100~150mm
C.100~200mm
D.200~300mm
参考答案:D
—He ______ a piece of waste paper then put it into the rubbish bag.
—We should learn from him. Everyone should do something to protect the environment. [ ]
A. picked up
B. threw away
C. gave away
D. handed in
预防风湿性心脏病加重的根本措施是()。
A.控制饮食
B.控制体重
C.长期服用阿司匹林
D.休息
E.预防和治疗链球菌感染