单项选择题
A.power B.speed C.resistance D.thrust force
We’d better （）economic speed （）fuel consumption.A.take；...
单项选择题We’d better （）economic speed （）fuel consumption.
A.take；save B.to take；save C.take；to save D.to take；to save
This machine （）out of order very often, but now it work...
单项选择题This machine （）out of order very often, but now it works well.
A.is used to be B.was used to be C.used to be D.was used to
When we arrived here yesterday, their ship （）for three ...
单项选择题When we arrived here yesterday, their ship （）for three days.
A.has left B.had left C.has been away D.had been away
