在标准状况下，560ml某气体的质量为1.1g，这种气体可能是（　　）

A．CO

B．N₂

C．CO₂

D．N₂O

The man didn’t know _________ the thief broke into the house and stole all his valuable things  

A．it was when that

B．when it was that

C．that it was when

D．was it when that