甲状旁腺细胞分泌
A.胰岛素B.降钙素C.甲状腺素D.甲状旁腺素
参考答案:D
I know Beijing very well since I ________ there three times.
A. have been B. went C. have gone
在选用发动机冷却液时,其冰点要比车辆运行地区的最低气温低()℃以上。
A.5
B.10
C.15