When it ______ research into heart disease and its effects on the body, we do not have adequate substitutes for the use of animals.
| A．refers to | B．related to | C．comes to | D．talks to |
I've made a mistake, though I didn't ________.
| A．intend | B．intend so |
| C．intend to | D．intend making |
Gone ________ when we were oppressed.
| A．are the days | B．the days are |
| C．the days have | D．the day is |
．—Did Linda see the traffic accident?
—No, no sooner ________than it happened.
| A．had she gone | B．she had gone |
| C．has she gone | D．she has gone |
The picture ________in my bedroom is painted by a famous artist.
| A．hanged | B．hung |
| C．being hung | D．hanging |
The beautiful girl ________a hair dresser for a year is a manager now.
| A．served | B．served as |
| C．serving | D．who served as |