用所给单词的适当形式填空。

1. If you_________ (wear) jeans to the party, the teachers_________ (not let) you in.

2. We are going to the party if it_________ (not rain) tomorrow.

3. If he_________(help) me with my English, I_________(be) successful.

4. What_________(happen) if they miss the train?

5. I will call you up when I_________ ( come) back.

6. I_________ ( real) don't know how to take photos.

7. I want __________ ( go) fishing tomorrow.

8. You should _________( stay) at home and _______( study) .

9. We __________ ( go) _________ ( shop) if it_________ ( not rain) tomorrow.

10. When is a good time_________ ( fish)?

如图所示，在倾角为a的光滑斜面上垂直纸面放置一根长为L，质量为m的导线，当通过如图所示的电流I时，为使它能静止于斜面上，应把它置于怎样的匀强磁场中（   ）

A．磁场方向垂直斜面向上，;

B．磁场方向垂直斜面向下，;

C．磁场方向竖直向下, ;

D．磁场方向水平向左，