That sounds interesting为什么加S

That sounds interesting为什么加S The song sounds very interesting.sounds为什么要加s sound interesting 为何不加,That sounds good 为何要加s,如果用that sounds That sounds good中的sounds为什么要加s That sounds great.sounds 为啥加s. That sounds boring.为什么sound加s啦 That sounds good.这里的sound为什么要加s? that(sounds)interesting对吗? that sounds good 为什么不是that‘s sounds good ? that sounds fun 为什么sounds要加s,单三不是主语是第三人称单数时加s吗,为什么这个要加s? playing tennis sounds interesting.中的play为什么加ing? That sounds interesting什么意思