The exercise consists of stretching and contracting the leg muscles.

此项训练包括伸展和收缩腿部肌肉。

In this exercise, the muscles are elongating rather than contracting.

在这项运动中，肌肉是在延伸而不是在收缩。

He developed full-blown AIDS five years after contracting HIV.

他感染艾滋病病毒五年以后，患上了完全型艾滋病。

Upon contracting government projects, the antecedent money for bidding may be reduced by up to 50%.

承揽政府工程时，押标金、得降低百分之五十以下。

Chapter 3 Scope of contracting.

第三章工程承包范围。