— Thank you. — .[ ]
A. Yes?
B. You're welcome.
C. No.
答案：B
下列发电方法与电磁感应原理无关的是（）
A、铅酸电池
B、水力发电
C、核电
D、火力发电
No sooner had we reached the top of the mountain ______ we all sat down to rest.
A. when B. thenC. than D. until
