引起植物发生双光增益效应的两种光的波长是
A. 450nm
B. 650nm
C. 大于685nm
______ the printer back into place.
A. Put
B. To put
C. Putting
D. Puting
Keep ________ heat.
A. away
B. from
C. away from
D. away with
I want to know __________ cars.
A. how to repair
B. repair how to
C. how repair to
D. to repair how