胸部叩诊过清音的叩诊特点是
A．以上都不是
B．空响(性质)
C．中等(时限)
D．响亮(指强度)
E．高(音调)
参考答案：A
积食泄泻的治疗首选( )
A．热者寒之 B．寒者热之 C．热因热用 D．塞因塞用 E．通因通用
-It's difficult for the village children to cross the river for school.
- I think a bridge _________ over the river. [ ]
A. was built
B. is being built
C. should be built
D. has been built
