Grammar if +past, would + infinitive 1) I ... (not know) what to do if I ... (find) a mouse in my kitchen
2) What ... you ... (do) if you ... (lose) your job
3) If my sister ... (be) older, she ... (come) with me to the party
4) My parents ... (buy) a bigger house if they ... (have) more money ​

Grammar if +past, would + infinitive
1) I wouldn’t know what to do if I found a mouse in my kitchen.
2) What would you do if you lost your job?
3) If my sister were older, she would come with me to the party.
4) My parents would buy a bigger house if they had more money.