Помогите исправить оплошности в предложениях:1. If you will do to London,

Помогите поправить оплошности в предложениях:
1. If you will do to London, visit Leicester Square.
2. I promise I come to the party this weekend.
3. Mark are helping me to move flat, on Saturday?
4. Look out! You're falling over if you are not careful!