Eis as respostas corretas:

1 – They (were ou weren´t) at the beach yesterday.
2 – I (am not) a stupid guy. (am também está gramaticalmente certo)
3 – (Do) you need glasses ?
4 – I (don´t) need help. I can do it alone.
5 – (Were) you tall when you (were) a child ?
6 – She has _________ to get up early every day. (Não colocar nada mesmo no espaço)
7 – I (was ou wasn´t) expecting to see you when I (was) in hospital that awful day.
8 – If you (don´t) come to my party you will not receive any souvenirs. (Também aceitei "nada" no espaço pois, apesar do significado estranho, fica correto gramaticalmente).
9 – She _________ had to go a few minutes ago. (Não colocar nada mesmo no espaço)
10 – That cute teddy bear (doesn´t) have brown fur like almost all the others.
Quase todo mundo errou esta 10. Não se pode deixar o espaço em branco pois o sujeito é singular (it) e não concorda com have.
11 – She (was, wasn´t, is, isn´t) kidding when she said she (was, wasn´t, is, isn´t) angry with you.
Mas o ideal nesta 11 é colocar wasn´t na primeira e was na segunda.
12 – (Have) you bought any magazines lately ?
13 – (Don´t) turn off the lights. It’s dark in here.
14 – These (are) good guys. You can trust them.
15 – It (is) a non-stop flight. It (doesn´t) stop anywhere.
Também aceitei was + didn´t
Obs – non-stop = adjetivo ; stop = verbo
16 – I _________ like him because he _________ dishonest.
Opções certas para a questão acima:
don´t e is
nada e isn´t
am not e is
am e isn´t
17 – Look ! The cars (are) crashing.
18 – Be prepared to watch a nice _________ show. (Não colocar nada mesmo no espaço)
19 – (Are) you with her ? (Aceitei were também)
20 – (Did ou didn´t) you talk to her when she (was) in Canada ?

Exercício 2:
Em qualquer língua a conversa precisa ter muitos sinônimos. O uso repetitivo das mesmas palavras torna a conversa chata, enfadonha, e faz a pessoa parecer alguém com pouco vocabulário, poucas idéias.
Nas frases do exercício abaixo o objetivo é sempre dizê-las duas vezes de forma parecida, justamente para mostrar a quem lê ou a quem ouve o seu bom conhecimento da língua.

Exemplo: How much is this book ? (cost)
A palavra em parênteses deve ser usada na segunda frase para formarmos uma semelhante. Para isso, obviamente, teremos que mudar a primeira e não vamos só acrescentar a outra palavra, devemos encaixá-la com o auxílio de outras, para tornar a frase gramaticalmente correta.
Então How much is this book? – How much does this book cost?

Vamos fazer o mesmo com:
How much money do you have? (dollars) – How many dollars do you have?
Do you have many friends ? (got) – Have you got many friends ?
A policeman´s job is very difficult. (has) – A policeman has a very difficult job.
São Paulo was the champion of 2008. (last year) – São Paulo was last year´s champion.
Geography is easier than Chemestry. (less) – Geography is less difficult than Chemestry.
That man is sweeping the floor. (by) – The floor is being swept by that man.
Fabio: "I don´t like liver." – Maria: "I don´t like liver either." (neither) – Neither do I.
She´s been living here for 3 years (2006) – She´s been living here since 2006.
I don´t have any friends. (no) – I have no friends.
This cell phone stopped working an hour ago. (for an hour) -This cell phone hasn´t been working for an hour.
She is so beautiful…(such) – She is such a beautiful girl…
Maria is my best friend´s girlfriend and she lives in Copacabana. (who) – Maria, who is my best friend´s girlfriend, lives in Copacabana.
I need some information. (two) – I need two pieces of information.