In spoken English we often use lots of or a lot of. In written English, it is more common to write many (for countable plural nouns) or a great deal of (for uncountable nouns) in positive statements. A common mistake is to use lot of. For example, "There are lot of accidents on this road". To avoid making this mistake, remember either to use a before lot, or to make lot plural – lots. We can say either a lot of or lots of before a noun. For example, "There are a lot of people here" or "There are lots of people here". There isn't any difference between the two expressions. We can also use a lot as an adverb to say how much you do something. For example, "She talks a lot". A lot is also used in short answers. For example, "Do you like swimming?", "Yes, a lot." http://www.english-at-home.com/grammar/using-lots-of/ a lot of and lots of , which carry the same basic meaning: a great deal of, are colloquial (i.e., informal) but nonetheless Standard and acceptable. lots of is considered more informal than lots of. There's no rule on usage: Both a lot of and lots of are used with plural count nouns and non-count nouns, like this, Plural Count Noun There are a lot of books in your bag. (OK) There are lots of books in you bag. (OK) Non-Count Noun There is a lot of milk left in your glass. (OK) There is lots of milk left in your glass. (OK) In terms of grammar, the verb agrees in number with the noun: if the noun is plural then the verb is plural, A lot of books were left on the table. Lots of books were left on the table. if the noun is not plural, then the verb is not plural, A lot of milk was left on the table. Lots of milk was left on the table. In academic writing, the more formal 'a great deal of' or 'many', with plural count nouns, and 'a great deal of' or 'much', with non-count nouns are used: Plural Count Noun There are a great deal of books in your bag. A great deal of books are in your bag. Non-Count Noun There is a great deal of milk left in your glass. A great deal of milk is left in your glass. In terms of meaning, speakers tend not to make a distinction between a lot of and lots of; both refer to a great quantity. But, for some speakers, lots of tends to mean, more than a lot of (i.e., a greater quantity). http://www.englishdaily626.com/qna.php?013

在网上有许多网站可以帮助你了解这个问题。 我查过几个： A Lot, Lots Of, A Lot Of These three expressions are used in informal English. They can mean either a great quantity of or a large number of and can be rather confusing at times. Here are the general rules for their use. A Lot Of / Lots Of These two expressions both mean a great deal of or several. They are used before a count or non-count noun. These two expressions tend to be used in informal English. Examples: We need a lot of people for this game. She likes lots of jam on her toast. A Lot Use a lot at the end of a sentence as an adverb. A lot is NOT followed by a noun. The meaning is the same as a great deal. Examples: I enjoy swimming a lot. Mary seems to travel a lot. http://esl.about.com/od/grammarintermediate/a/cm_lot.htm