In America, if__________friend has invited you to drop by anytime, it is__________best to call before visiting to make sure it is convenient for him.
| A．a; a | B．a; 不填 | C．the; a | D．the; 不填 |
The news shocked the public，__________ to great concern about students' safety at school.
| A．having led |
| B．led |
| C．leading |
| D．to lead |
Plastic bags are provided for our convenience but they have also __________ the pollution of the environment.
| A．referred to |
| B．led to |
| C．reacted to |
| D．attended to |
Look over there-there's a very long, winding path __________ up to the house.
| A．leading |
| B．leads |
| C．led |
| D．to lead |
The printer is of good quality. _____ it break down within the first year, we would repair it at our expense.
| A．Would | B．Could | C．Might | D．Should |
Maintaining(维持) peace and stability of the South China Sea and the East China Sea will certainly ____ a more promising Asian-Pacific area.
| A．contribute to | B．belong to | C．compare to | D．devote to |