He was puzzled by this phenomenon. He began to try every approach _________ the best way of working it out.
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A
known to find
B
knowing to find
C
known finding
D
knowing finding
推荐题目
— What made your skin look so terrible? — _______ to the sunlight for a long time.
#95390
A
Because it was exposed
B
After being exposed
C
Being exposed
D
Exposed
Carbon dioxide(CO2)_______ from burning fuels is the most common of the so-called greenhouse gases.
#91467
A
producing
B
having been produced
C
to be produced
D
produced
---- What do you think of the book ? ---- Oh excellent. It’s worth _________ a second time.
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A
to read
B
to be read
C
reading
D
being read
As a student, every minute should be made use of _______.
#90806
A
study
B
to study
C
studying
D
studied
__ carefully if any change occurs when doing experiments in the lab..
#88398
A
Observe
B
To observe
C
Observed
D
Observing