当今世界的时代主题是（）
A.战争与革命
B.科技与创新
C.纷争与动乱
D.和平与发展
参考答案：D
The reason ______ he gave for being late was ______ he overslept this morning.
A．why; that
B．which; that
C．why; because
D．which; because
组织中沉积的钙盐在HE染色时，下列哪项描述是正确的()
A．红色颗粒状
B．黑褐色颗粒状
C．蓝色粗颗粒状
D．粉红色颗粒状
E．黄褐色颗粒状
