在净化系统中,共涉及到了()、()、()、()四种风机。
参考答案:主排烟机;高压;罗茨;反吹
_______ the same mistake again made his parents unhappy; ______ by his parents, he left ______ .
A.His being made; criticizing; disappointed
B.He has made; criticized; disappointed
C.He had made; criticized; disappointing
D.His making; criticized; disappointed
甲、乙和丙,一位是山东人,一位是河南人,一位是湖北人。现在只知道:丙比湖北人的年龄大,甲和河南人不同岁,河南人比乙年龄小。由此可以推知()。
A.甲不是湖北人
B.河南人比甲年龄小
C.河南人比山东人年龄大
D.湖北人年龄最小