违约责任是合同当事人不履行合同义务或者履行合同义务不符合约定时，依法产生的法律责任。
参考答案：对
Unable to move because of the injury in his leg, Jack was forced to wait _____ he was, wrapped
in Michael's jacket.[ ]
A. who
B. where
C. what
D. when
设f(x)二阶可导，且
，则f(0)=______．
，则f(0)=______．