нужно React to the following situations using shouldn’t / shouldn’t + Perfect Infinitive (for expressing critics or disapprovement) or needn’t / needn’t + Perfect Infinitive (for expressing the absence of necessity).

e.g. They talk at the lesson. – They shouldn’t talk at the lesson.
They talked at the lesson. – They shouldn’t have talked at the lesson.
e.g. He phones me every day. – He needn’t phone me every day.
He phoned me every day. – He needn’t have phoned me every day.

1) These people are waiting for us.
2) This man bothers us all the time.
3) My brother asks me too many questions.
4) Our chief often gives us advice.
5) She always worries about her children.
6) You look tired because went to bed very late yesterday.
7) I ate too much chocolate and now feel sick.
8) You washed this shirt but it wasn’t dirty.
9) I bought the cheese which was necessary.
10) I left home without an umbrella and got wet.

Mouse - mice
Goose - geese
Puppy - puppies
Sheep - sheep (без S)
Goldfish - goldfish (без S)
Guinea pig - guinea pigs
Turtle - turtles
Budgie - Budgies (скорее всего так, но не уверен)
Wolf - wolves
Если на конце буква 'y' то во множественном числе она меняется на -ies
Если на конце буква 'f' или 'fe' (wolf, wife) то во множественном числе они заменяются на -ves (wolf - wolves, wife - wives, myself - ourselves)
Есть просто слова, которые надо запомнить (sheep - sheep)
А так же неисчисляемые существительные (они обозначают не количество, а продукт или вещество в целом (fish - fish (не 1 рыба, а рыба в целом, как понятие))). У таких слов S в конце во мн. числе не ставится.

Found - основать
Founding
(This university was founded by M. V. Lomonosov. - Этот университет был основан М. В. Ломоносовым.)
P.S. Так же found это 2 и 3 формы глагола find (находить).

I was sure she would pass that exam
I am uncertain about my future career
His story was not real
They presented their false documents to the officers
I think being a pilot is the toughest job  
The easiest way to solve the problem would be to borrow some money
It's difficult to find a well-paid job
Nowadays university graduates often have to contend with poorly-paid jobs
It's very courageous of him to help his friend with his problem
If I were him, I wouldn't act so cowardly and would have talked to the teachers
High school is often a very stessful experience beacause of bullying and peer pressure 
I find going to spa salons very relaxing