泪膜的水液层主要由()和()分泌形成。
参考答案:主泪腺;副泪腺
—By the way,have you moved into the new house?
—Not yet.The walls ________.
A.were painted
B.are being painted
C.are painted
D.are painting
()就是企业的大顾客,他们占企业顾客数量的20%,却给企业带来80%甚至更多的利润。
A.重要顾客
B.关键顾客
C.一般顾客
D.无关顾客