he is trying to draw a house on the blackboard

he is trying to draw a house on the blackboard
he is trying(to draw a house)on the blackboard 对括号里的部分提问
What is he ______ ______ ______on the blackboard?
Manatees eat (about 100 pounds of food)a day 对括号里的部分提问
_____ _______ do manatees eat a day ?
There used to be (a lot of trees )near here.对括号里的部分提问
_______ _______ ________ to be near here?
第三个没错,但第二个错了是：Manatees eat (about 100 pounds of food)a day 对括号里的部分提问
_____ ______ _______ do manatees eat a day ?