下列何者不是人体的主要淋巴器官?()
A.胰脏
B.脾脏
C.胸腺
参考答案:A
尿素是一种常见的化肥,化学式为CO(NH2)2.
(1)尿素的相对分子质量______.
(2)求尿素中各元素的质量比.______
(3)求尿素中氮元素的质量分数.______.
It’s John’s birthday today. I wish I _____ her out to a superb restaurant for dinner, but I’m too busy recently.
A.can take
B.take
C.could take
D.had taken