the nice drink that----cool-----the boy very sick last night

the nice drink that looks cool made the boy very sick last night.

* the nice drink that looks cool 是主语 that 后跟的从句修饰 drink 所以是单数一般现在时

* 主语为drink 是单数（虽然在这个句子里没有什么影响）
last night 过去， 所以用一般过去时 即 made

looks made