①They are planting trees.（对划线部分提问 划线trees）
What are they planting?
②She cuts the cake.（现在进行时）
She is cutting the cake.
③The students are having a maths exam.(一般疑问句）
Are the students are having a maths exam?
④The students are working hard.(对划线部分提问 划线hard）
How are the students working?
⑤He does his homework at four.(用now改写）
He is doing his homework now.
⑥The students are cleaning the room now.(对划线部分提问 划线cleaning the room)
What are the students doing now?
⑦Peter and Bob read books in the classroom.(现在进行时）
Peter and Bob are reading books in the classroom.
⑧The girls are singing and dancing.(对划线部分提问 划线singing and dancing）
What are the girls doing?
⑨They learn English in the evening.(现在进行时态）
They are learning English now.