It _____ to chat online all day long. You’d better do something else.
At the gate _____ a soldier _____ uniform.
The doctor warned Pat against smoking as soon as possible and _____.
–Jack is good at maths and doesn’t perform well in English. –_____.
It is these poisonous products _____ can cause the symptoms of the flu, such as headaches and aching muscles.
–Are you coming to Jeff’s party? –I’m not sure. I _____ go to the concert instead.