30． the people have become masters of their own country that science can really serve the people.
| A．Only then | B．It is only when | C．Only when | D．It is only then |
The father as well as his three children ____ skating on the frozen river every Sunday afternoon in winter.
| A．is going | B．go | C．goes | D．aregoing |
We live day by day，but in the great things the time of days and weeks ____ so small that a day is unimportant.
| A．is | B．are | C．has been | D．havebeen |
An iron and steel works, with some satellite factories, ____ to be built here.
| A．are | B．were | C．is | D．will |
Here is a message of importance to every man and woman who ____.
| A．vote | B．votes | C．are voting | D．voted |
"All____present and all ____ going on well."our monitor said.
| A．is; is | B．are; are | C．are; is | D．is; are |