Hi, could I ask two questions, please?<br/>Are the following two sentences both grammatically correct?<br/>If yes, then what’s the difference between them?<br/><br/>Sentence 1:She was heard singing in the room by Brad.<br/>Sentence 2:She was heard to sing in the room by Brad.<br/><br/>Are the verbs “sing” and “singing” should be transformed to “to sing” in the passive because of the verb of perception “heard?”<br/><br/>Thank you.