After reading for an hour, you'd better_______ the green trees for a minute or two.

A．look out of

B．look out at

C．look out from

D．look for at

甲状腺主要合成和分泌（）

A.甲状腺素和三碘甲状腺原氨酸

B.TBG

C.TRH

D.TSH

E.一碘甲状腺原氨酸