See also

Note:
Pinyin#Pinyin tone marking

A virus is a tiny parasite which can infect living organisms. It is made only of a nucleic acid + a protein coat. Usually the nucleic acid is RNA; sometimes it is DNA.

Bìngdú shì wēixiǎo de jìshēngchóng, kě chuánrǎn huó de shēngwùtǐ. Tā zhǐ yóu yīgè nucleic acid + yīgè dànbáizhì wàiké zǔchéng. Nucleic acid tōngcháng shì RNA, yǒushí shì DNA.