Combine the two sentences by using a relative clause. Some of them need a comma
1. John didn't study for the exam. That was a very stupid thing to do
=>John didn't study for the exam which was a very stupid thing to do.
2. We flew to New York in the Concorde. It is the fastest passenger plane in the world
=>We flew to New York in the Concorde which is the fastest passenger plane in the world.
Combine the two sentences by using a relative clause. Some of them need a comma
1. John didn't study for the exam. That was a very stupid thing to do
=> John didn't study for the exam which was a very stupid thing to do
2. We flew to New York in the Concorde. It is the fastest passenger plane in the world
=> We flew to New York in the Concorde which is the fastest passenger plane in the world
