________ the problem, he wouldn't have committed those mistakes.
| A．If he understood | B．Had he understood |
| C．When he had understood | D．If he would understood |
It is no use trying to talk him into studying hard; he can only be by force.
| A．upset | B．harmed | C．rescued | D．persuaded |
This pop star is very ______ with young people, who like his songs and style.
| A．familiar | B．similar | C．particular | D．popular |
Susan advised me not to buy the vase, but I bought it _____.
| A．anyhow | B．however | C．though | D．totally |
Scientists in some countries have done a lot of work to _____ the moon.
| A．cover | B．search | C．explode | D．explore |
She does not know _____ the situation, for she is too inexperienced.
| A．how to deal with | B．what to deal with |
| C．how to deal with it | D．what to do with it |