Singular noun is a noun that assigns to one thing, one person and one idea. Example: Boy, Girl, Father, Mother, Man, Doctor and so on.
Laura's attempt at trying to use an English idiom reveals that she is eager to try English phrases and expressions.
She says "There's no use trying to drink spilt milk," and even though her use of the idiom is incorrect (it should be - there's no use crying over spilt milk), she still really wants to try and better her English speaking skills, which is always quite commendable.
C) I would say. You can learn many things from rollercoasters, like how much mass they can hold. The distance they go in a daily trip. Rollercoasters can be of use for science for a fun learning experience!
