An uncountable noun is marked [ U ] in this dictionary. 不可数名词(UN)在本词典中以[U]标明。
As a noun,'travel'refers to the activity in general and is generally used as an uncountable noun. travel做名词的时候指的是旅行这种行为本身,通常用作不可数名词(UN)。
Note than in the first example above notice is an uncountable noun so it cannot take a / an. 第一种表达中,notice是不可数名词(UN),所以前面不需要加a/an。
Used before an uncountable noun ( abstract, material, proper ) to refer to a countable meaning of noun. 用在不可数名词(UN)(抽象、物质、专有)前,使该名词作为可数名词的用法。但当不可数名词(UN)前有表示数量的复数名词时,谓语动词用复数形式。
The word is an uncountable noun and is used in a general sense, hence ( therefore ) it takes no article. 这个词是不可数名词(UN),又用于一般意义,所以不要加冠词。