根据问句选答句，将其序号填入题前括号内。(10分)
( )（1）What's the time?
( )（2）What's your number?
( )（3）What's your mother?
( )（4）What's eight and nine?
( )（5）What class is he in?
| A．I'm number five. | B．It's seventeen. |
| C．It's seven o'clock. | D．She's a doctor. |
E．He is in Class Four，Grade Five.