干式系统开启末端试水装置的试水阀后（）应动作。
A、加速器
B、报警阀
C、水流指示器
D、压力开关
E、雨淋阀
参考答案：A, B, C, D
某国政府向企业和居民发行20年期国债，这种信用属于（）。
A.直接信用
B.国家信用
C.间接信用
D.商业信用
E.消费信用
This is ___________. It is very cold. I put on my scarf, hat and mittens.
This is ___________. It's warm and rainy. The flowers bloom.
This is ___________. What a hot, sunny day!
This is ___________. It's cool. The ___________ blows the leaves off the trees.