表示選擇關(guān)系的連詞：主要有or, either … or, or else, whether … or, otherwise等。如Which do you like better, tea or coffee? Either you leave this house or I’ll call the police. Do it at once, or else! = Do it at once, otherwise you will suffer in some way. Take a taxi, otherwise you won’t get there in time. 表示因果推理關(guān)系的連詞：主要有so, for, then, therefore等。