Being short of money, I made a virtue of necessity and gave up smoking.
我因缺钱,倒也乐得把烟戒了。
The doctor asked us to call him during the night except in case of necessity.
医生吩咐我们,除非必须,否则不要在夜里叫他。
She realizes with a sudden wave of sympathy that Charlotte, a rather homely girl of advancing years, married Mr. Collins out of necessity, fearing a lonely and poverty-stricken life as an old maid.