闸阀的特点是什么?
参考答案:
(1)流动阻力小、结构长度小、启闭较有力。
(2)介质流动方向不受限制、启闭时间长。
(3)密封面易擦伤、结构复杂、成本高。
______ attractions you are planning to visit in that island country, you'd better book your hotel _____
because the hotels are always full in the tourist seasons. [ ]
A. Whatever; in the advance
B. Wherever; before hand
C. Whichever; in advance
D. Whosever; before hand
下面不是供应链管理模式的是( )。
A.以制造企业为主导的供应链模式
B.以零售企业(连锁超市)为主导的物流服务供应链模式
C.以3PL(集成物流供应商)为主导的物流服务供应链模式
D.以采购销售为主导的供应链模式