单项选择题
A.interferes B.disturbs C.upsets D.interrupts
During the war she always kept a（）of tinned food in the...
单项选择题During the war she always kept a（）of tinned food in the house.
A.load B.substitute C.conservation D.reserve
The ratio of the work done by the machine（）the work don...
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.
A.against B.with C.to D.for
His inability to learn foreign languages was a(n（）to hi...
单项选择题His inability to learn foreign languages was a(n（）to his career.
A.objection B.defect C.obstacle D.depression
