急性胰腺炎首发的临床表现是（）。

A.恶心、呕吐及腹胀

B.发热

C.血钙降低

D.腹痛

E.低血压或休克

—I want to be a Chinese teacher when I grow up.

—That's great. Chinese teachers ______ in China and some foreign countries. [ ]

A. need

B. are needing

C. are needed

D. will need