Verified answer

1) Thousands of workers see this website every day.

This website is seen by thousands of workers every day.

2) The employers asked the staff for their opinions.

The staff were asked for their opinions by the employers.

3) A mechanic is repairing my bike at the moment.

My bike is being repaired by a mechanic at the moment.

4) Somebody has found the missing document.

The missing document has been found.

5) Somebody made this clock in Switzerland .

This clock was made in Switzerland.