1, these exercises were done well
=>they did these exercises very well
2, this dress must be washed in cold water
=>they must wash this dress in cold water
3, No mistakes have been made in his composition
=>he haven't made any mistake in his composition
4, His painting will be exhibited for the first time by New Arts gallery
=>New Arts gallery will exhibit his painting for the first time.
5, This house was built 100 years ago
=>they built this hou e 100 years ago
6, These artificial flowers are made of silk
=>they make these artificial flowers of silk
7, The lesson are being written by the student now
=>the students are writing the lesson now
8,This job has to be done at once
=>they have to do this job at once
9,These animal at the zoo are fed twice a day
=>they feed these animal at the zoo twice a day
10, The operation is going to be performed by French doctor
=>a French doctor is going to perform the operation