探测器的作用是

A．优化射线的能谱

B．减少患者辐射剂量

C．减少噪声和振动

D．吸收低能量X射线

E．接收X射线

情景对话。

A: Is this 1. ______ your brother?

B: 2.______, he is.

A; What's 3. ______?

B: His name is Peter Brown.

A: 4. ______is his birthday?

B: It's May 23rd.

A: 5.______?

B: He is 14 years old.

A: 6.______ does he like?

B: He likes basketball.

A: 7. ______ you have a basketball?

B: Sorry, I 8. ______ have. But my brother, Peter, has one.

A: Really? Let's go to find him.

B: OK! Let's 9. ______ basketball together.

A: That 10. ______ great.