【单选题】The old man bought a ticket ______.
A.
after he got on the train
B.
before he got on the train
C.
as soon as the conductor told him to buy one
【多选题】B2B网上交易市场 从交易空间范围进行划分为( ) 。
【判断题】储藏期间进行合理的通风换气是马铃薯安全储藏的一个重要措施
【简答题】光衰减器主要有两种类型:( ),( )。
【单选题】-- When did you_____? -- I’ve_____ _for two months.
A.
got married; been married
B.
be marred; been married
C.
get married; got married
【简答题】某火电厂有两台机组共同向负荷供电,其耗量特性和约束条件分别为: F 1 =0.02P 1 2 +2P 1 +10t/h , 20MW≤P 1 ≤60MW ; F 2 =0.03P 2 2 +3P 2 +16t/h , 20MW≤P 2 ≤60MW ; 求当有功功率负荷为 80MW 时的经济分配 方案, 并计算最优分配方案比平均分配方案每小时节约多少煤炭 。
【单选题】He soon ______from failure, and promised to work harder than before.
【单选题】They ________ with each other for two years before they got married. [ ]