在砖墙基体镶贴饰面砖时,用______打底。
A.1:1.5水泥砂浆
B.1:3水泥砂浆
C.1:3:9水泥混合砂浆
D.1:1:6水泥混合砂浆
参考答案:B
强心苷治疗心房颤动的主要目的是()。
A.恢复窦性心律
B.降低心房率
C.降低心室率
D.减少栓塞发生率
E.使心房颤动转变成心房扑动
Clothing made of man-made materials has advantage over _______ made of natural ones like cotton, wool or silk.
A.one
B.what
C.that
D.the ones