下列洋流中，以信风为动力的是（    ）

A．巴西暖流

B．北赤道暖流

C．加利福尼亚寒流

D．北大西洋暖流

句型转换

1. You'd better take out the trash. (改为否定句) 

    __________________________________

2. It's a very boring thing. (改为感叹句) 

    __________________________________  

3. I have to study for the math test.（改为否定句）

    __________________________________

4. She cleans her room twice a week. (划线部分提问)

    __________________________________

5. He's making his bed. (对划线部分提问)

   __________________________________