英语条件句(Conditional Sentences)按其意思可分为真实条件句(Sentences of Real Condition)和非真实条件句,亦称虚拟条件句 (Sentences of Unreal Condition)。这种句子实际上包含两个子句,即if子句(if-clause)和结果子句(result—clause),也就是我们习惯所称的条件从句和主句。为了讨沦的方便,本文以“子句”和“结果子句”相称。不管是真实条件句,还是非真实条件句,这两种子句中动词的时态和形式都比较复杂。因而,在时态和形式的选择和运用上要十分谨慎。首先 Conditional Sentences can be divided into Sentences of Real Condition and Non-Real Condition Sentences, also known as Sentences of Unreal Condition. This sentence actually contains two clauses, the if-clause and the result-clause, which are what we used to call conditional clauses and main clauses. In order to facilitate the discussion, this article “clauses” and “result clause” commensurate. The verb tense and form of these two clauses are more complicated both in real conditions and non-truth conditions. Therefore, be very cautious in the choice and application of tense and form. First of all