妈妈和爸爸拍手的英文表达是 "mom and dad clap their hands"。
这个表达的来源是源自于英语语言中 "clap" 这个动词，其本意是指用手掌击打两下以表示称赞或鼓励。
下面是一些使用 "mom and dad clap their hands" 的英文例句：
"When the pttle boy finished his piano recital, mom and dad clap their hands and gave him a big hug."（小男孩弹完钢琴演奏后，妈妈和爸爸拍手并给了他一个大大的拥抱。）
"The crowd erupted into cheers and applause as the actors took their final bows, and even mom and dad clap their hands in excitement."（演员们走完最后的鞠躬时，观众齐声欢呼与掌声，甚至妈妈和爸爸也拍手表示兴奋。）
"The young girl beamed with pride as she received her award, and mom and dad clap their hands with joy and tears in their eyes."（这个年轻女孩得到奖项时，面带自豪之情，妈妈和爸爸拍手庆祝，眼中含着眼泪。）