当显微镜视野很暗影响观察时,应当调节光亮程度,此时应采取的措施是 [ ]
A.选用大光圈
B.换高倍目镜
C.选用平面镜
D.调节准焦螺旋
A
2)根据下面一段对话内容,从对话下边方框内的选项中选出能填入空白处的最佳选项,其中两项为多余选项。 A: Oh, hi, Tess! I’m sorry. I’m thinking about something. B. ____(16)____ A. I am. I havea chance to go onatour. B: A tour What kind of tour A- A music tour. ____(17)____. B- Wow! That’s great. They are pretty famous. A- ____(18)____. B: So you’re going to do it A. I don’t know. ____(19)____. B: It sure would! Where will the tour go A: ____(20)____. B: How long is the tour A: Four months. B:OK, wish you a happy travel! A:Thank you!
A.This tour is the chance of lifetime. B.It goes all over North America and South America. C.It looks like you’re dreaming about something. D.You’ll have to quit school and your job at the store. E.My agent wants me to go on a tour with Art’s Jazz Band. F.Have you told anyone about this yet G.It would be a great opportunity!
香港在城市建设中采取“上天”(建设高层建筑)和“下海”(填海造陆)两种措施的主要原因是( )
A.建筑水平高
B.资金充足
C.人多地少
D.海景秀丽