【判断题】不定期租船运输不定线、不定港、不定时。( )
【单选题】_____ keep the insects out, she shut the window. [ ]
【判断题】金属结晶后的晶粒越小,晶界数量越多,则性能越差。
【判断题】金属结晶后的晶粒越小,晶界数量越多,则性能越好。
【单选题】How do librarians keep books in order?
A.
They arrange the books in alphabetical order.
B.
They put the books into a card catalogue.
C.
They give a number to each book.
D.
They put the books on the shelves.