.It is uncertain whether the medicine will work on the this cold, _________？
A. won't it B. isn't it C, will it D. is it
John brought over my letter _______ to him by mistake.
| A．delivered | B．to be delivered |
| C．delivering | D．having delivered |
_______ here if you want to get a better view of the mountain scenery.
| A．To come | B．Coming | C．Comes | D．Come |
--- Can I help you?
--- Yes. I bought an iPhone 6 here last week, but there _______ something wrong with it.
| A．was | B．had been | C．will be | D．is |
He promised that he ______ us in the party, but he hasn’t turned up until now.
| A．will join | B．had joined |
| C．would join | D．has joined |
There are about one million words in English. ________, most people use only about ten thousand of them.
| A．Moreover | B．However | C．Otherwise | D．Therefore |