. ___ to nuclear radiation, even for a short time may produce variants(变异体)of genes in human bodies.
___ my friend Mary sends me a beautiful card on my birthday.
The doctor ___ the boy and examined his back.
He found the boy ___ on the wall.
If you ___ nature, you will not succeed in the end. A. go with B. go against C.against D, be against
Do you __ your son to be a doctor?