为防止在站台边缘装卸重物时使门槛变形，勿使屏蔽门门槛承受超过（）的设计载荷。
A.120kg
B.150kg
C.140kg
D.130kg
参考答案：B
China's population is expected to increase to about 1.5 billion in 2040, ______it will start to decline slowly.
A．where
B．which
C．on which
D．after which
新生儿上腭中线和齿龈部位有散在黄白色、碎米大小隆起颗粒，称为（）
A.马牙
B.螳螂子
C.痄腮
D.发颐
E.口疮
