this, that, these, those作为限定词的用法
作限定词时，this和that用于单数名词词组中，名词词组既可以是可数的也可以是不可数的。 These和those要用于复数名词词组中。例如：
Whoever had come up with this idea deserved a medal. 无论是何人提出这个主意都该获得奖牌。
But what happens when all this money is used up? 但当这些钱用完以后会发生什么事呢？
I hope to enjoy that feeling again before too long. 我希望过不了太久会重新享受那种感觉。
Someone put that book there after the murder, to make it look as if he’d been reading when he was killed. 有人在谋杀他之后把那本书放在那里以造成他在读书时被杀的印象。
These chairs have the great advantage of being much cheaper than conventional ones. 这个椅子具有比普通椅子便宜得多的优势。
You think if those people still have him they’ll keep him alive. 如果他还在那些人的手里，你认为他们会留他一条活路吗？