如图所示刚架梁上作用均布荷载时，弯矩图（）正确。
A.A
B.B
C.C
D.D
参考答案：C
Unless ____ to speak, you should remain silent at the conference.
A invited B inviting C being invited D having invited
鸟类胚胎的后肠产生的盲状突起将分化成为（）。
A.羊膜
B.浆膜
C.尿囊
D.卵黄囊
