问题
选择题
—______he at home now?
—Yes, he is. He is______computer games. [ ]
A. Is; playing
B. Does; play
C. Do; playing
D. Is; plays
答案
答案：A
搜题请搜索小程序“爱下问搜题”
—______he at home now?
—Yes, he is. He is______computer games. [ ]
A. Is; playing
B. Does; play
C. Do; playing
D. Is; plays
答案：A
抽制细线时可用激光监控其粗细，如图所示，激光束越过细丝时产生的条纹和它通过遮光板上的一条同样宽度的窄缝规律相同，则
| A．这是利用光的衍射现象 | B．这是利用光的干涉现象 |
| C．如果屏上条纹变宽，表明抽制的丝细了 | |
| D．如果屏上条纹变宽，表明抽丝的丝粗了 |