这个句子是个强调句,根据上下文判断,句中的it是强调it,而不是指代上文中的a huge smile.(she gave a huge smile),上句已很明确是她发出的笑容,下句不可能再重复说 her smile (it) was her smile,所以只能把it 理解为强调it,去掉it was....that这个强调句,句子还原为her smile made her whole face light up last night. 这样上下文句意就是通顺的。