A sentence has been given in Active/Passive Voice. Out of the four given alternatives, select the one which best expresses the same sentence in Passive/Active Voice.
A Sonar of a ship sends sounds waves of speed 1600 m/s. These waves are reflected back by the ocean floor in 4 seconds. Find the depth (in m) of the ocean floor.
In the following question, some part of the sentence may have errors. Find out which part of the sentence has an error and select the appropriate option. If a sentence is free from error, select 'No Error'.
We had to return because(A)/when we reached the railway(B)/station the train left.(C)/No error(D)