a) Complete the sentences using Past Simple or Present Perfect.
Example: They ... in a new project. (to take part / last year)- They took part in a new project last year.

1)The scientist ... his article.(to write \ already)-

2)Andrew's hamster ... his food,(to eat \ just)-

3) The boys ... an old cage in their garden. (to find \ yesterday)-

4) They ... the problem. (not \ discuss \ yet )-

5) Charles ... his translation. (to finish \ just )-