They were surprised that a child should work out the problem____ they themselves could not.
A.once | B.unless | C.while | D.if |
Our professor told us that salt water _____ at a lower temperature than fresh water.
A.is freezing | B.was frozen | C.freezes | D.froze |
Until recently historians assumed that calendars ________ with the advent of agriculture.
A.came to existence | B.came to existing |
C.came to exist | D.were existential |
. ________ when the boulders suddenly disappeared.
A.So relieved we felt | B.How relieved we felt |
C.What a relief we were feeling | D.How we felt relieved |
________ from endless homework on weekends, the students now find their own activities, such as taking a ride together to watch the sun rise, more colourful.
A.Freed | B.Freeing | C.To free | D.Having freed |
When he knew the disappointing result of the exam, he seemed quite _______.
A.fed up | B.cast down | C.in vain | D.in amazement |