After months of voyage, Columbus arrived in what later to be a new continent.
| A．had been proved | B．was proved | C．had proved | D．proved |
Please make sure all the lights are ______ before you go to bed.
| A．turned on | B．turned down | C．switched off | D．switched on |
If you have decided which bike to buy, you can ______ for it on the Internet and we will send it right to your home.
| A．take an order | B．carry out an order | C．keep order | D．place an order |
Studies show that people are more ______ to suffer from back problems if they always sit before computer screens for long hours.
| A．likely | B．possible | C．probable | D．sure |
I’m sure your suggestions will _____ the problem.
| A．contribute to solving | B．contribute to solve |
| C．be contributed to solve | D．be contributed to solving |
______ in the sandstorm, he didn’t know which way to take.
| A．Having stuck | B．Stuck | C．To be stuck | D．Sticking |