You’re __ your time trying to persuade him; he’ll never join us.
| A．spending | B．wasting | C．losing | D．missing |
I haven’t found my watch yet; in fact, I’m not sure ____ I could have done with it.
| A．where | B．whether | C．what | D．how |
I was advised to arrange for insurance ____ I needed medical treatment.
| A．nevertheless | B．although | C．in case | D．so that |
They were surprised that a four-year-old boy should work out such a difficult problem ____ they themselves couldn’t.
| A．once | B．then | C．while | D．if |
I think you ought to end it ____ it is too late, or you’ll kill yourself.
| A．even if | B．before | C．so that | D．once |
The girl got herself into a serious situation ____ she was likely to lose control over the motorbike.
| A．where | B．which | C．while | D．why |