No,they 're still working on it.是否可以改为：No,they're still repairing it 疑问句是：Have your machanices finished yet?如果working on it不能改为repairing it的话,请帮忙说明是为什么?

No,they 're still working on it.是否可以改为：No,they're still repairing it 疑问句是：Have your machanices finished yet?如果working on it不能改为repairing it的话,请帮忙说明是为什么?
No,they 're still working on it.是否可以改为：No,they're still repairing it
疑问句是：Have your machanices finished yet?
如果working on it不能改为repairing it的话,请帮忙说明是为什么?

No,they 're still working on it.是否可以改为：No,they're still repairing it 疑问句是：Have your machanices finished yet?如果working on it不能改为repairing it的话,请帮忙说明是为什么?
well,personally speaking,yes.可以改成的.work on sth.表示从事某事 = get down to sth.