Mister Wright mentioned some additional detail I overlooked when verb "to be" is used with nouns : "is" follows single nouns,while "are" follows plural nouns. He gave already an example. I would like to comment on his answer though: I am sure you know it right ,but Dennis could get possibly confused by the way you demonstrated it. The statement that "is" is used for single subjects will not apply to personal pronouns all the way as a rule ,since with the 'single' Subject personal pronoun " I " , "am" is rather used than "is ". In the case of those pronouns it is rather the peculiar conjugation of the verb that applies, while "is" and "are" don't necessarily follow the singularity or plurality of the personal pronouns, unlike the cases of nouns where they follow the grammatical number of the noun.

There are simple rules in English grammar, it is a dead formula that we can not changed. I am (first person) you are (second person) he is, she is (third person) it is ( third, single) "Are" used in first, second and third people or things in plural form

Both "is" and "are" are forms of the verb "to be". The form "is" is used for singe subjects, and "are" is used from plural (more than one) subjects. Here is a conjugation: I am He is She is We are You are They are Here are 2 sample sentences: This car is fast. Those cars are fast.

Hello Dennis, Verb " to be " in English * which almost equals　是　in Chinese * is conjugated as follows: I am You are He/she is We are They are So basically in the simple present tense you will be using "is" with the third singular person: He /she /it is You use "are " with the second ,fourth and fifth person: You are We are They are When using other tenses that consists of verb "to be" with a participate for example : - the present continuous tense verb 'to be' + verb + ing i am learning You are learning ...etc Again here "is" and "are " will be used with the same persons as in the present tense . He /she is learning We are learning etc

I will add a few thoughts. Collective nouns (nouns which name a group) use singular verbs when acting as a unit, but plural verbs when the individuals in that group are acting independently. Examples: "The class is going on a field trip." Here, even though a class is many people, the word "class" is replaced by the pronoun "it" and uses "is", because the GROUP is acting as ONE unit. "The army is prepared to deploy." Again, the whole army is acting as ONE unit. "The class are from several different countries." Here, the plural ("are") matches, because the "class" cannot be from different countries as ONE unit, but as individuals. Here, the pronoun replacement would be "they" and not "it".