Always use the safety belt and buckle your child in immediately after putting her in the booster seat. Even if your child's belted in safely, never leave her sitting in a booster seat unattended. Hold off on using booster seats without belts, such as the plastic cube-shaped seats you often see in restaurants, until your child's about 36 months old. These seats are not only dangerous because they lack safety belts, but they're also missing straps for securing the booster to a chair.
Noun. 1. trough-a narrow depression (as in the earth or between ocean waves or in the ocean bed). natural depression, depression-a sunken or depressed geological formation. swale-a low area (especially a marshy area between ridges).
Wave Action at the Waterâs Surface. A wave in the ocean has the same basic shape as many other waves. â¢ The crest is the high point of the wave. â¢ The trough (trawf) is the low point of the wave. â¢ Wave heightis the vertical distance between the top of the crest. and the bottom of the trough.