Hold hands while you walk is a imperative sentence.
Answer: question 1 would be on the computer as he is not inside it.
question 2 would be on as the time is on top of the watch.
question 9 would be behind as trailed means to drag behind.
question 14 would be at the gate.
question 16 would be on the beach as the waste is on top of the beach.
question 17 would be at the table as the children are not sitting on top of the table.
Explanation:
My dad used to say that the city lights always look best at midnight.