_____opportunity has not found any sign of life, the presence of water means life is possible．
A．WhileB．Because
C．WhenD．Since
At the meeting, the boss announced that all things ________ into consideration, the planned trip would have to be called off．
A．takenB．taking
C．to takeD．being taken
Most students in our class prefer taking pains in our studies to _____ with a better education．
A．equipB．equipping
C．be equippedD．being equipped
Take an active part in the activities you enjoy ____ you can make many friends．
A．whereB．whenC．thatD．what
----How long have you been in this office?
----Just a few minutes．I_____ here together with my cousin。
A．have walkedB．had walked
C．have been walkingD．walked
We should look up to him as a shinning example of _____ to duty．
A．devotionB．privilege
C．responsibilityD．burden
