The bell ________ the end of the period rang, ________ our heated discussion.

[　　]

A．indicating; interrupting

B．indicated; interrupting

C．indicating; interrupted

D．indicated; interrupted

The research is so designed that once ________ nothing can be done to change it.

[　　]

Don’t use words, expressions, or phrases ________ only to people with specific knowledge.

[　　]

 －－How do you deal with the disagreement between the company and the customers?

－－The key ________ the problem is to meet the demand ________ by the customers.

[　　]

Cleaning women in big cities usually get ________ by the hour.

[　　]

The little girl, ________ at the examination results, stood there without saying a word.

[　　]

Scientists say it may be five or six years ________ it is possible to test this medicine on human patients.

[　　]

Parents should take seriously their children’s requests for sunglasses _________ eye protection is necessary in sunny weather.

[　　]

The bridge is made ________ stone while wine is made ________ grapes.

[　　]

Great changes ________ ________ in our village.

[　　]

A．have been taken place; in the last few years

B．have taken place; in the last few years

C．take place; in the past few years

D．took place; in the past few years