穿越秦岭，连接关中盆地与四川盆地的铁路线是（）A.宝成线 B.成渝线 C.成昆线 D

—_____ do you like the film?      

—It is very interesting .     [ ]

A. What        

B. Which        

C. When            

D. Why

完成句子，使改写后的句子完整，并与原句意思相符，注意每空只填一个单词。

1. Although he is a child, he is good at taking photos.

   Although he is a child, he ___________ ___________ ___________ taking photos.

2. They plan to go to Hong Kong for vacation.

   They __________ __________ to Hong Kong for vacation.

3. Our English teacher often rides to school.

   Our English teacher often__________ to school __________ a bike.

4. Could you play the violin at the age of five?

   __________ you __________ to play the violin at the age of five?

5. I have four apples. Jack has six apples.

  I have  __________ apples __________ Jack.

从使用的角度评价彩色多普勒血流显像仪，质量差的标志是（）

A.空间分辨力、速度分辨力、动态分辨力都高

B.检出低速血流敏感度高

C.显示彩色血流图像均匀性好

D.彩色血流效果佳

E.提高灰阶图像增益时，彩色图像质量即下降

在相同条件下，为什么鼓风机的效率冬季比夏季高？

简述风杯测风速原理？