🧩 词语组成解析
this
[ðɪs]
pron. 这，这个;这事，这人;这时;下面所说的事;
adj. 这，这个;刚过去的，即将到来的;今…，本…;
adv. 这样地;就是这样;这么地;
is
[ɪz]
vt.& vi. 是（be的三单形式;
n. 存在;
🗣️ 情景例句
Advice doesn't normally come cheap, but this piece is for free...
通常来说，忠告都是价值不菲的，但这个是免费赠送的。。。
Which one is more economical?
哪一个是比较经济的？
and another group were disturbed for an equal period of time but when they were no exhibiting eye-movements,
另一组人也是连续几夜被叫醒，但是在眼球队没活动时被叫醒的。