补全对话。

A:I'm not feeling well. I 1. ______ ( have)  a cold.

B:It is cold outside. You should put on more clothes.

A:2. ______ you.3.______ (be) to the hospital yet?

B:Yes, I 4.______ ( go)  to see a doctor this moming and he 5.______  ( give)  me some medicine.

A:6.______ you 7______ (take) the medi-cine?

B:Yes,  I 8.______ ( take)  it just now.

A:lt is nothing serious. You should drink plenty of water and get some rest.  I think you'll9.______  (be) all right

soon.

B:I hope so. By the way, where is our monitor?

A:She 10.______ ( go)  to the play-ground.

某研究人员模拟赫尔希和蔡斯的关于噬菌体侵染细菌实验，进行了如下实验：①用³²P标记的噬菌体侵染未标记的细菌；②用未标记的噬菌体侵染³⁵S标记的细菌；③用¹⁵N标记的噬菌体侵染未标记的细菌。一段时间后进行离心，检测到放射性存在的主要部位依次是（）

A.沉淀、上清液、沉淀和上清液

B.沉淀、沉淀、沉淀和上清液

C.沉淀、上清液、沉淀

D.上清液、上清液、沉淀和上清液