English plurals: a hard task

Although forming plurals is thought to be a quite easy grammatical phenomenon, it is a mistake that I have to correct very often in my students' writings. Of course, it is very easy to form plurals like cat-cats, country-countries or even some irregulars (mouse-mice, foot-feet), at least the most common ones. 
However, forming plurals can prove a dangerous task, so you'd better take this quiz to check your knowledge. If you do well, don't bother reading the rest of this post. If you don't, I recommend revising your grammar.

For those how didn't do well in the quiz, I believe you'll find the following rules quite interesting and helpful!


Uncountable nouns
These are some of the uncountable nouns:
advice
baggage
luggage
money
machinery
news
hair
garbage
information
lightning
rubbish
nonsense
These nouns 1) can not be used in plural
                       2) are followed by singular verbs (is, not are)
                       3) to count them, we use "some, any, little" etc

Same singular and plural
deer
fish
sheep
swine
cod
salmon
trout
Chinese
Japanese
Portugese
Swiss
aircraft
gymnastics
mathematics
physics
politics
series
species

Nouns ending in -f or -fe form the plural with -s
belief 
chief
proof
turf
roof
safe
handkerchief
cliff etc.

But, nouns ending in -f or -fe form the plural with -ves
calf
half
knife
leaf
self
shelf
wife
wolf
loaf
thief

Nouns ending in -o form the plural with -s
dynamo
kilo
photo
radio
piano
studio
tango
OR with -es
cargo
hero
mosquito
negro
potato
tomato
tornado

Words with greek origin such as crisis, emphasis, praxis form the plural in -es (emphases, crises etc.)

Words with latin origin such as phenomena, criterion, larva, form the plural according to latin grammar:
phenomenon-phenomena
criterion-criteria
larva-larvae 
nucleus-nuclei