摘要：I don't watch TV very much nowadays. There's so much rubbish on. It's not like it used to be. （我现在不太看电视了。垃圾太多了。不像以前了。）
today的字面义是“今天”，只有一天。但也被泛义成“现在、当下、与过去相比”。
these days围绕“今天”，肯定不止一天，大体相当于“近来”。
Nowadays的尾巴s不是复数标记，而是副词属性格标记，就如同always和forwards两个单词尾巴上的s。
Nowadays相当于now+a+day+-s, 字面义是“现在每一天”，即“现今、目前、现在”。
三种表达在“最近、现今、目前”的语义，差不多互换。如下面这个例句，
【例句1】Young people nowadays don't respect their teachers any more. (现在的年轻人不再尊重他们的老师了。)
下面这个句子的watch容易有单次事件感，若就nowadays换成today, 容易想起“只是今天”。
【例句2】I don't watch TV very much nowadays. There's so much rubbish on. It's not like it used to be. （我现在不太看电视了。垃圾太多了。不像以前了。）
注意nowadays不要写成nowdays。
These days是口语，不太正式，如
【例句3】These days you never see a young person give up their seat for an older person on the bus. That's what I was taught to do when I was a kid. （如今，在公共汽车上，你永远不会看到年轻人为老年人让座。而这是我小时候被教导要做的事情。）
【例句4】Pop singers these days don't seem to last more than a couple of months, then you never hear of them again. (这些天的流行歌手似乎只持续了几个月，然后你就再也听不到他们了。)
Today相对正式，
【例句5】Apartments today are often designed for people with busy lifestyles. (如今的公寓通常是为生活繁忙的人设计的。)
these days和nowadays不宜用所有格，但today完全没问题，如
【例句6】Today's family structures are quite different from those of 100 years ago. （今天的家庭结构与100年前大不相同。）
也可以用of所有格(nowadays是副词，不能加of所有格)，如
【例句7】The youth of today have never known what life was like without computers. (今天的年轻人永远不知道没有电脑的生活是什么样子的。)
注意nowadays, these days和today不宜用作形容词，如
【例句8×】The nowadays cars / The these days cars / The today’s cars …
但副词[短语]可以后修饰名词，如
【例句9】Cars nowadays/these days/today are much more efficient and economical. （现代的汽车更高效、更经济。）
来源：西亚教育
