CORRECT: The police is sure that they know who was responsible for the vandalism.
The police are sure that they know who was responsible for the vandalism.
CORRECT: I found out a useful information at the meeting.
I found out some / a piece of useful information at the meeting.
CORRECT: I need to buy a new pants for my interview tomorrow.
I need to buy some new pants/a new pair of pants for my interview tomorrow.
CORRECT: They have some beautiful furnitures in their house.
They have some beautiful furniture in their house.
Gymnastics is / are my favorite sport.
Gymnastics is my favorite sport.
CORRECT: The homeworks were very difficult last night.
The homework was very difficult last night.
We've made a lot of progress / progresses in the past few weeks.
We've made a lot of progress in the past few weeks.
Luke's clothes look / looks really expensive.
Luke's clothes look really expensive.
CORRECT: We had a beautiful weather when we were on vacation.
We had beautiful weather when we were on vacation.