355. Doctors warned against chewing tobacco as a substitute for smoking.
譯文
醫(yī)生警告說，咀嚼煙草是吸煙的另一種形式。
點睛
warn sb. against sth./doing sth.意為“讓某人警惕或提防某事（或不要做某事）”。如：
1) He warned us against pickpockets. 他警告我們，要小心扒手。
2) He warned me against going there at night. 他警告我，晚上不要到那兒去。
考點歸納
warn一詞的用法還包括：
后接從句，即warn sb. that...意為“提醒／警告某人……”。如：
I warned them that there might be snakes in the woods. 我提醒他們樹林里可能有蛇。
warn (sb.) of sth.意為“提醒（某人）某事”。如：
The police are warning (motorists) of possible delays. 警方正在提醒（駕駛員），交通可能受阻。
后接不定式，即warn sb. to do sth.意為“提醒／告誡某人做某事”。如：
She warned them to be careful. 她告誡他們務(wù)必小心。
