At a very young age, Professor Field used to ______ books on radio.[ ]

A. devote to translating

B. devote himself to translate

C. be devoted to translate

D. be devoted to translating

The connected joints of pipe，usually made of three joints of pipe approximately 90 feet long，racked in the derrick when making a trip are called a（）.

A.string

B.stand

C.joint

D.standpipe