Gyōza ni wa nōyaku ga konnyū shite ita.The dumplings were contaminated with pesticides.

do no yōhō no saigo wa【daidōshi】desu. Daimeishi no dōshi ban. Eigo wa onaji tango o nankai mo tsukau no o kirau no de, dōshi mo nikaime wa do ni shite shimau koto ga yoku arimasu.The final usage of do is as ‘pro-verb’, the verb version of a pronoun. Since English doesn't like to use the same word again and again, it is common to use do in place of the verb the second time.

Miyamoto ShigeruShigeru Miyamoto (video game designer)

sumaho no ura ni shīru o harustick a sticker on the back of a smartphone