Some words that end in -s are singular. Some important examples are:
a. billiards, draughts and other names of games ending in -s
Draughts is an easier game than chess.
b. measles, rabies and other names of illnesses ending in -s
Rabies is widespread in Europe. We hope we can keep it out of Britain.
c. athletics, politics, mathematics and other words ending in -ics
The mathematics that I did at school has not been very useful to me.
Ten o'clock. Here is the news.