实验法的特点是什么？

磷化的酸比指的是（）。

A、总酸比游离酸

B、游离酸比总酸

C、总酸比促进剂

D、游离酸比促进剂

I couldn't ________. The line was busy.[ ]

A. go by

B. go around

C. get in

D. get through

设计新实验：

在下列的SQL语句中，属于数据控制语句的是( )。 Ⅰ．CREATE Ⅱ．SELECT Ⅲ．UPDATE Ⅳ．GRANT Ⅴ．DROP Ⅵ．DELETE Ⅶ．ALTER Ⅷ．INSERT Ⅸ．REVOKE

A．Ⅰ、Ⅴ、Ⅵ、Ⅶ

B．Ⅳ、Ⅸ

C．Ⅱ、Ⅲ、Ⅵ、Ⅷ

D．Ⅰ、Ⅴ、Ⅶ

In nautical terminology a dog is a（）.

A.crow bar

B.device to force a water tight door against the frame

C.heavy steel beam

D.wedge