Question

there is a lot of traffic in this city，so look both ways before crossing the street。both是副词吗

Answer 1

Both，本身有三个词性，adj, adv, pron,
在这儿是形容词！adj, 因为后面跟的是可数名词复数，指二个办法。。。
权威解释和例句(来自牛津字典）：
adj,
(with pl ns; the n may be preceded by a def art, a demons det or a possess det 与复数名词连用, 名词前可有定冠词﹑ 指示限定词或所有格限定词) the two; the one as well as the other 二者; 两者都: hold sth in both hands 双手拿着某物 * Both books/Both the books/Both these books are expensive. 这两本书都很贵.
adv.
~... and... not only... but also... 不但...而且...; 既...又...; 又...又...: be both tired and hungry 又累又饿 * She spoke both French and English. 她既会说法语也会说英语. * Both his brother and sister are married. 他的哥哥和姐姐两人都已婚.
Pron
~ (of sb/sth) (referring back to a pl n or pron 复指前文之复数名词或代词) the two; not only the one but also the other 二者: He has two brothers: both live in London. 他有两个兄弟, 都住在伦敦. * His parents are both dead. 他父母双亡. * We both want to go to the party. 我们俩都想去参加聚会. * I like these shirts. I'll take both of them. 我喜欢这种衬衫. 我两件都要.

有问题还可以再问。

Answer 2

both是限定词（与复数名词连用）两个，两个都
它这儿明显是修饰ways的，修饰名词的怎么可能是副词？

Answer 3

应该是形容词吧

Answer 4

不是是数量词

Answer 5

形容词吧

Answer 6

不是，是名词！