属于封闭式引流的是（） A.片状引流 B.管状引流 C.纱条引流 D.负压引流 E.

北京的 * * 城楼是个轴对称图形．______．

Construction is expanding all over China, no doubt many materials will be needed at a very big amount in future.

A．China, no doubt many materials will be needed for a very big amount

B．China, no doubt many materials will be needed in a very big amount

C．China; no doubt many materials will be needed in large amounts

D．China; no doubt many materials will be needed for large amounts

组织实施思想政治教育应当坚持的原则？

下列表达式有错误，正确的写法应该是 【6】 。 [(a+b) +c]/80-5÷(d+e)