If I were you，I would take an umbrella.
If I had any money with me，I could lend you some.
If I had got there earlier，I should/would have met her.
If he had taken my advice，he would not have made such a
从句：①if+主语+were to do
If he should come here tomorrow，I would talk to him.
If there were a heavy snow next Sunday，we would go skating.