loop pulsing

例句：

1. 1. The rope is wrappedaround the tree to hold it up.
   绳子绕在树上以支撑它。
2. 2. The carwas parked in a loop around thecorner.
   汽车停在街角的环路里。
3. 3. The loop of wire is holding thedoor shut.
   这根电线圈正在把门关紧。