病毒
an infective agent that typically consists of a nucleic acid molecule in a protein coat, is too small to be seen by light microscopy, and is able to multiply only within the living cells of a host.
示例:• The common cold is caused by a virus.普通感冒是由病毒引起的。• Scientists are working to develop a vaccine against the new virus.科学家们正在努力开发针对新病毒的疫苗。同义词:pathogengermmicrobe