After working until midnight for two weeks, he finally ______ and had to stay in the hospital.
| A．broke up | B．gave in | C．broke down | D．gave up |
I _____ you yesterday, but you weren’t in.
| A．rang | B．rang to |
| C．rang with | D．rang to |
No matter how much you’ve learned and how high a standard of education you have had, you must _______ the people heart and soul.
| A．serve | B．serve for |
| C．serve to | D．serve on |
. If you want to sell your product you must _____ it.
| A．advertise | B．advertise for |
| C．advertise on | D．advertise to |
New medicines and instruments ______ every day to extend life.
| A．develop | B．are being developed |
| C．are developing | D．have developed |
A red sky in the morning ______ to be a sign of bad weather.
| A．says | B．is saying |
| C．has said | D．is said |