Gosh, I can't tell you the rule, but I can tell you the difference in the meanings from a colloquial understanding, how I would understand it if we were having coffee

1. Before my parents come, I will have cleaned my house.

2.I will be cleaning my house before my parents come.

In the test i confuse in which brackets put future perfect or continuous?

Could you tell me the key worson these tenses!

Thanks.

1 - The house will be clean when they arrive. Your parents are coming. Before they arrive, you will clean your house. Your house will be clean. When did you clean the house? Yesterday? Last week? This morning? - Hmmmm - doesn't really matter. What matters is that your house is clean. When your parents walk in that door, your house will be clean. What's most important is the outcome. The house is clean.

2- You are going to spend time cleaning your house. I will be cleaning my house - it's important that cleaning will occur. Yes, the result is that the house will be cleaner, but will it be completely clean? You will have done some cleaning, but God only knows if it will be clean enough to make your parents happy. When will you clean it? Although the sentence doesn't say exactly, from a coloquial position it seems like you will be cleaning it right before they arrive. You will clean the house in the morning and they will be arriving that afternoon.

As a native speaker I can't help with the rules. And I could be wrong. But that's what it would mean if I were having a conversation with someone.

Good Luck on your test.

Laurie