已知有三种微粒的结构示意图如下： (1)请选用A、B、C序号填空： ①属于同一元
题型：填空题
问题：
已知有三种微粒的结构示意图如下：
(1)请选用A、B、C序号填空：
①属于同一元素的不同微粒的是 。 ②属于阴离子的是 ，属于阳离子的是 。
(2)上述三种微粒中，能形成化合物的化学式是 。
题型：填空题
阅读理解。
1. When does the train X504 leave Washington?
A. 9:00.
B. 9:30.
C. 10:00.
D. 10:30.
2. If you have to get to New York before 12:00, you'd better take _________.
A. X500
B. X501
C. X502
D. X503
3. Which of the following trains does not stop at BWI Airport?
A. X502.
B. X503.
C. X504.
D. X505.
4. If you want to go on weekends, you can NOT choose _________.
A. X501
B. X502
C. X503
D. X504
5. Which of the following is true according to the timetable?
A. You can have meals on most of the trains.
B. Most of the trains do not stop at Neward Int'l Airport.
C. You can't buy a ticket at the stations without reservation.
D. Nobody can get from Princeton Junction to Metropark on January 30.