have to 变一般疑问句时在句首加DO
2 把must 提到句首.如
They have to clean the floor .-> Do they have to clean the floor
They must clean the floor .-> Must they clean the floor
加油!不明白再问!
have to 变一般疑问句时在句首加DO
2 把must 提到句首.如
They have to clean the floor .-> Do they have to clean the floor
They must clean the floor .-> Must they clean the floor
加油!不明白再问!