everybody began to laugh and sing 中的began 是及物动词还是不及物动词?

everybody began to laugh and sing 中的began 是及物动词还是不及物动词? At that moment ,everybody began to laugh and sing . everybody began to laugh and sing为什么laugh和sing不用过去时 everybody began to laugh and sing.为什么后面不是过去时? At that moment,everybody began to laugh and sing同义句、、快些嗯. 英语新概念小问题第二册第九课有一句：at the moment,everybody began to laugh and at last sha made the baby()and began to laugh The pianist began to play and the girl in red began to sing it began to rain.中的rain是动词还是名词 At last he b________a singer and began to sing song. The day broke,______birds began to sing. At last, Lucy make the baby ____ and the baby began to laugh