如图所示，矩形线圈有N匝，长为a，宽为b，每匝线圈电阻为R，从磁感应强度为B的匀
题型：选择题
问题：
| 如图所示，矩形线圈有N匝，长为a，宽为b，每匝线圈电阻为R，从磁感应强度为B的匀强磁场中以速度v匀速拉出来，那么，产生的感应电动势和流经线圈中的感应电流的大小应为（ ） A．E=Bav， B．E=NBav， C．E=Bav， D．E=NBav，  |
题型：选择题
阅读理解。
Lifts are very useful. Why? Think about a tall building. You work on the thirtieth floor. Maybe you can walk
up all the stairs one time. But can you climb thirty floors to your office every day? Of course not.
In an old lift, a worker is needed. He or she operates it up and down. In a modern lift, there is no worker.
People can operate it themselves.
Do you know how to use a lift? OK, let me tell you. For example, you want to go to the twelfth floor from
the ground floor. First, you must press the button (按键)▲, then the door opens. After that you can get into the
lift. Third, you press the 
, and the door closes. Fourth, you press the number 12, then the lift takes you
up to the twelfth floor. When the door opens again, you can get out of the lift. If you want to go down to the
first floor, you must press the▼, then do the same. It takes you down there. It is very easy and fast. Now can
you use it?
根据短文内容，判断下列句子正误，正确的写“T”，错误的写“F”。
( ) 1. In a modern lift, people can operate it by themselves.
( ) 2. If you want to go upstairs, you must press the ▼.
( ) 3. If you want to go down to the first floor, you must press the ▲.
( ) 4. In a tall building, it is very easy and fast for you to go up and down in a lift.
( ) 5. Lifts are just used for the old people to go up and down in a tall building.