句型1
if only引起的感叹句，相当于 “How I wish + 宾语从句”，意思是“但愿……；要是……就好了”
[例句]
If only he could come! 他要是能来就好了！
If only we students didn’t have so much homework！要是没有这么多的作业该多好！
If only I hadn’t been so careless in the exam! 我当时没有那么粗心就好了！
句型2
if it were not for… (= were it not for…)
if it hadn’t been for… (= had it not been for…)“要不是因为有……；如果不是……”
