When filled with a gas______ lighter than air, a balloon becomes buoyant and rises.A．muchB

Before starting an air compressor, It should be _____.A.unloadedB.primedC.filled with wate

A（n) ______ is a destructive program that fills a computer system with self－replicating in

Charging is the filling of the engine cylinder with a supply or charge of fresh air _____

In a（n)______ universe filled with stars, every line of sight should eventually meet the s

It can be learned from the passage that Internet history has______.A．been filled with wars

Researchers discovered that plants______with a virus give off a gas that activates disease