Several English words end with an “s” in their singular form. Most of these don’t pose any problem; few people would say “the kiss were beautiful” instead of “the kiss was beautiful”. However, there are a few that commonly cause problems:
News
Although the equivalent expression in many languages would be in the plural, “news” is a singular noun, so you should say:
Oddly enough, “news” is uncountable, which means that not only is it followed by a singular verb, but you also cannot say “a news”:
Lens
Unlike “news”, “lens” is countable, so you can try to remember that if there can be “two lenses”, there must also be “one lens”:
Series
To make things even more confusing, the plural of “series” is also series. You should therefore use a singular verb if you speak about one particular series, e.g. “my favourite TV series has been cancelled”, and a plural verb if you speak about several series at a time, e.g. “all the series of the Unknown Channel are good”.
Means
Similarly to “series”, “means” is already both the singular and the plural form. For example, “railway is a means [singular] of transportation, but there are also several other good means [plural] of transportation.
Bellows
A “bellows” is an instrument used for blowing air. Like “series”, the plural of “bellows” is also “bellows”, so you have to use a singular verb when speaking about one bellows and a plural verb when speaking about more than one.
Measles
Measles is a disease, and as you have probably noticed from the previous sentence, the word is in the singular:
Quite naturally, it is uncountable, i.e. you cannot have “two measles”.
Plural nouns that learners think are singular
In addition to the words above, there are a few words which only have a plural form and might be confusing for some learners if the equivalent expression in their mother tongue is in the singular:
jeans, tights, trousers, pants
All this hosiery is used only in the plural (usually because they come in pairs—for both legs—and the singular form has died out):
tongs
Not to be confused with “thongs”, the plural of “thong” which is a type of underwear, “tongs” are the same case as above: