—I wonder what makes you a good salesperson．
—I as a waiter for three years，which contributes a lot to my today's work．
| A．serve | B．have served |
| C．had served | D．served |
Dorothy was always speaking highly of her role in the play, ____, of course, made the others unhappy.
| A．who | B．which |
| C．this | D．what |
He made another wonderful discovery, ______ of great importance to science.
| A．which I think is | B．which I think it is |
| C．which I think it | D．I think is |
He’s got himself into a dangerous situation _____ he is likely to lose control over the plane.
| A．where | B．which |
| C．while | D．why |
I met the teacher in the street yesterday ________ taught me English three years ago.
| A．which | B．when |
| C．where | D．who |
Is this all that you need? If you married me, I’d give you everything you _____.
| A．want | B．wanted |
| C．had wanted | D．are wanting |