---What are you busy with ?
--- We are carrying out a research _______ the causes of cancer.
| A．into | B．onto | C．to | D．in |
Great changes_____ in the small city in the last 20 years.
| A．have taken place | B．took place | C．had taken place | D．are happening |
----Kate really upset Granny.
-----I’m sure she didn’t______.
| A．want so | B．mean to | C．have to | D．hope so |
----Why did you go back to the shop?
-----I left my friend _____there.
| A．waiting | B．to wait | C．wait | D．waits |
I advise you to give up smoking for it is _____to your health.
| A．harm | B．harmless | C．harmful | D．harmfully |
I don’t doubt _____he will come next week.
| A．that | B．if | C．what | D．when |