To understand the grammar of the sentence, you must break it into parts. 
| A．down | B．up | C．off | D．out |
On the other hand, the influence______ eating habits on people’s emotions was also neglected most of the time.
| A．to | B．on | C．of | D．at |
It was announced that only when the fire was under control_______to return to their homes.
| A．the residents would be permitted | B．had the residents been permitted |
| C．would the residents be permitted | D．the residents had been permitted |
Tea ceremony, though it is now most popular in Japan, is said_______ in ancient China.
| A．to have been originated | B．to be originating |
| C．to have been originating | D．to have originated |
My friend has returned from the UK. She ______ at Oxford for four years, during which we communicated with each other on the Internet.
| A．studied | B．has studied | C．had studied | D．has been studying |
It _______ come as no surprise that Suri Cruise wants to be an actress, since her father, Tom Cruise, is a Hollywood top star.
| A．can | B．should | C．will | D．must |