在对称三相电压作用下，对称三相电路产生的三相电流也对称。

Debbie got up early last Saturday morning. She wanted  1  in Green Park with some ot her friends. She was very happy about it.  2  she was ready, she got on her bike and left for the park – it was on the other side of the town. Suddenly, as she was riding fast, she  3 sirens (警笛). The sound of the sirens was getting  4 , so Debbie looked  5 her to see what was happening. As a result (结果), she fell off her bike and lay in the middle of the road. Luckily, Debbie wasn’t hurt,  6  a car hit her bike. After the car   7  , two men got out and started running.  8  , a police car stopped next to the same car and three policemen got out and started running after the two men. One of the policemen shouted, “Stop the thieves (贼)!”
  9  a policeman came to see Debbie. He thanked her because, in a way, she had helped them   10  .

小题1:	A．goes to skate B．go skating C．going to skate D．to go skating

小题2:	A．While B．As soon as C．If D．As quickly as

小题3:	A．heard B．listened to C．found D．saw

小题4:	A．close and close B．closer and closer C．big and big D．bigger and bigger

小题5:	A．after B．in front of C．behind D．before

小题6:	A．because B．so C．but D．and

小题7:	A．fell over B．passed away C．turned back D．stopped

小题8:	A．A few minutes later B．Just then C．After an hour D．Very fast

小题9:	A．In a few days B．Sometimes C．Some time later D．At the same time

小题10:

A．get out of the car B．run after the two men C．catch the thieves D．shout at the thieves