把句子变成被动语态
1.They laughed at home.2 They will build the bridge.3He took good care of the baby.4Can you finish it in two hours.5The students often do such exersices in class 6They are making machines .7 The task has been finished by us（变主动语态） 8They allowed--------（enter）the room 9.The teachers allowed us to ---------(go)in.(变被动语态,还要填空）