( )1.You're driving too fast. Have you noticed that there is a speed________of 40 miles per hour along this road?
A．range B．border
C．enquiry D．limit
( )2.He makes it a________to put some money aside each month.
A．discipline B．principal
C．principle D．essential
( )3.—Let's try operating the machine right now.
—Wait. Better read the ________ first.
A．instructions B．explanations
C．information D．introduction
