I would like to play with you, _______ I have to do my homework first.

根据短文内容，从A、B、C、D四个选项中选择正确答案填空。

    Children often  1 this game. They play it like this: Six 2 stand in a row(排) 3 the class. They put their hands 4 their backs(背), so you can't see their hands. The teacher gives one of them 5 rubber. The rubber goes 6 one student to another -- first one way, then the other. They must keep their hands behind their backs. The other students in the class keep their eyes    7. They can't look.

    Then the teacher says: “Stop and put your hands  8 you now.” Now the other students 9 their eyes, and guess who has the rubber. They ask questions like: “Li Lei, is it in  10 right hand?” They can have only five guesses.

如图所示，太阳能路灯的顶端是太阳能电池板，它白天向灯杆中的蓄电池充电，而夜晚则由蓄电池给路灯供电．下列关于太阳能路灯中能量转化的说法正确的是（）