[译] 做饭时我们应该洗手，以防止感染传播。
[误] Preparing food, we must wash our hands to guard spreading infection.

[正] Preparing food, we must wash our hands to guard against spreading infection.
[注] 动词 guard 作“提防”解时是不及物动词，后面须跟介词 against，又如：One must guard against one’s bad habit. 人们应防止恶习。