单项选择题
This machine works very well so long as no one（）with it.
A.interferes B.disturbs C.upsets D.interrupts
单项选择题 During the war she always kept a（）of tinned food in the house.
单项选择题 The ratio of the work done by the machine（）the work done on it is called the efficiency of the machine.
单项选择题 His inability to learn foreign languages was a(n（）to his career.
