当分泌的激素不足时会引起血钙下降的内分泌腺是（）。
A.甲状腺
B.肾上腺
C.垂体
D.甲状旁腺
E.松果体
参考答案：D
In order to perform the monitor function, language learners have to satisfy at least three conditions. One of the conditions is ______ to monitor his production.
A. enough speech B. much informationC. sufficient material D. sufficient time
就业协议的解除分为（）。
A.单方擅自解除
B.单方依法或依协议解除
C.三方解除
D.学校解除
