光在哪，神在那。

If-clauses 條件語氣

------------------------------------------------------------------------------------------

I. conditional

if-clause     main clause

0. zero/ general conditional (general truth 普遍真理)

ex: If it rains in April, the crop is good.

       (present simple)          (present simple)

1. first/ particular conditional (particular situation 特殊情況)

ex: If the sun comes out, the room will be hot.

        (present simple)               (future simple)

附屬子句沒有未來式，用現在式代替。

2. second/ imaginary conditional 和現在事實相反

ex: If I were better at tennis, I would play more often. 

        (past simple)               (would + V. )

3. third/ imagined conditional 和過去事實相反

ex: If I hadn't looked in the cupboard, I wouldn't have found the hammer.

        (had + p.p.)                                      (would have + p.p. )

should       have+p.p.   過去該做，卻沒做

shouldn't   have+p.p.   過去不該做，卻做了

4. mixed conditional

If Helen had left earlier, she would be on the train.    3+2

  (had + p.p.)                        (would + V.)

If he were a good student, he would have studied for the test.  2+3

    (past simple)                                      (would have +p.p.)

I thought by now we would have learned the lesson that if we ignore overhead, we will underestimate our expenses.

II. other conjunctions

III. omitting if

※ 插入號/詞