1、属于部分倒装，当虚拟条件句中含有 were，had，should，could等动词时，可以将if省略，然后将 were，had，should，could 等词移至句首： 2、 1. If he should fail，he would kill himself. →Should he fail，he would kill himself. 万一失败，他就会自杀。 3、 2. If I were you，I would do it at once. →Were I you，I would do it at once. 假若我是你，我就会马上做。 4、 3. If I could do it，I would. →Could I do it，I would.垍