问题
不定项选择
| 不定项选择 |
| 如图所示，在光滑水平面上固定一条形磁铁，有一小球以一定的初速度向磁铁方向运动，如果发现小球做减速运动，则小球的材料可能是（ ） |
 |
| A．铁 B．木 C．铜 D．铝 |
答案
CD
搜题请搜索小程序“爱下问搜题”
| 不定项选择 |
| 如图所示，在光滑水平面上固定一条形磁铁，有一小球以一定的初速度向磁铁方向运动，如果发现小球做减速运动，则小球的材料可能是（ ） |
|
| A．铁 B．木 C．铜 D．铝 |
CD
用方框中所给的单词的适当形式填空，使短文正确、通顺。每词限用一次。
 Many large cities have a subway system. The subway is called tube in London. In San Francisco, it is called BART (Bay Area Rapid Transit). Some subway systems, like Chicago’s, are quite 小题1:____________. It opened in 1897. Others are more recent (近代的). For example, Mexico City’s subway 小题2:____________ in 1969. Most subways are very modern and clean, but sometimes they get very小题3:____________. So people have to follow certain rules to make the trip more 小题4:____________. In London, when people use the tube, they must stand on the right so that people in a 小题5:____________ can walk on the left. They let passengers get off the train before others get on, and people are expected to give their 小题6:____________ to the old and disabled people. Some subways 小题7:____________ excellent services. In most subways, there is a station about every one kilometer. Trains 小题8:____________ at a station about every two minutes. Subways carry a lot of passengers. The number of people 小题9:____________ one way each hour in London can be about 30,000. However, in some other cities it is much higher. Hong Kong’s subway小题10:____________ the record of about 80,000 passengers an hour! |