女性生殖系统结核多见于以下哪个部位（）
A. * *
B.乳腺
C.输卵管
D.子宫颈
E.子宫内膜
参考答案：C
氮进入生态系统的三条途径是生物固氮、高能固氮、______。
It is normal for kids to feel anxious and not to be able to ______ their studies just before a quiz or
an examination. Parents should try their best to help them relax within their power. [ ]
A. settle down
B. devote to
C. get down for
D. settle down to
