undertook的解释，在云词典中undertook是什么意思？

undertook

[ˏʌndә'tuk]
vbl.
undertake的过去式

Grouped in12 teams, we undertook strict military training.
我们分成了12个队，进行了严格的军事训练。
He got less than he reckoned for when he undertook the job.
他得到的收入要比他接受这份工作时所估计的少。
He undertook to defend this attitude.
他开始为这一态度辩护。
In the end Zeus undertook to free her if they swore never more to rebel against him; and this each in turn grudgingly did.
后来宙斯答应释放她，条件是大家要起誓永不再造反。诸神们虽然满心的不情愿，但还是个个作了保证。
Next he undertook to pay off the debts.
然后他同意负责偿还债务。
She undertook responsibility for the changes.
她承担了这些变革的责任。
The lawyer undertook the case without a fee.
这律师免费承办那个案件。