Forests are very important because they provide us with fresh air and food

Forests are very important because they provide us with fresh air and food.
句意：森林非常重要,因为它们为我们提供了新鲜空气和食物.对划线部分提问划线because they provide us with fresh air and food我要的是划线提问，亲提问：Why are forests very important?为什么森林很重要？解释：对原因提问，用why。