清洁验证的关注点是()
A.清洁方法和程序;
B.清洁剂和清洁效果;
C.清洁对象和地点;
D.残留物检测仪器和方法;
参考答案:A, B, D
板块构造学说认为( )
A.地中海的缩小和珠穆朗玛峰的抬升都是板块张裂形成的
B.是板块的运动造成了大陆的漂移
C.全球共分为七大板块
D.地震多发生在板块的内部
–I bought a digital camera in the store near our school yesterday.
--Really? Why not buy it on the Internet? It’s _________.
A.more expensive
B.less expensive
C.expensive
D.the most expensive