These continual _____ in temperature make it impossible to decide what to wear.
| A．alterations | B．vibrations | C．waves | D．fluctuations |
.The majority of the damage ______ easy to repair.
| A．is | B．are | C．were | D．Be |
.Four-fifths of the crop ______.
| A．are ruined | B．was ruined | C．were ruined | D．have been ruined |
.Three-fourths of the buildings ______.
| A．was destroyed | B．is destroyed | C．were destroyed | D．has been destroyed |
.Early to bed and early to rise ______ a man healthy, happy and wise.
| A．making | B．to make | C．make | D．Makes |
.Mathematics ______ the language of science.
| A．is | B．has been | C．are | D．have been |