泵站工必须携带浓度测试仪,每班检查乳化液浓度不少于()次。
A.4
B.3
C.5
D.2
参考答案:D
.Shopping online can_____both convernience and choice, but not _____ websites aresafe enoung for shopping.
A.charge;either
B.supply; any
C.offer; all
D.provide; both
“征免性质”栏应填()。
A.一般贸易
B.一般征税
C.进料加工
D.来料加工