He learnt tractor maintenance.

他学会了拖拉机维修。

youdao

He should have either kept up with the maintenance of the tractor, or taken it out of use altogether.

BBC: Thomas Phizacklea

The volunteers are expected to carry out the full duties of the paid wardens - driving the tractor, mowing the grass, looking after the island's sheep, carrying out DIY and maintenance work on Flat Holm's buildings, and leading tours of visitors.

BBC: South East Wales - Volunteers wanted for island life