Questions 9-15
· Look at the notes below.
· Some information is missing.
· You will hear two people discussing an invoice.
· For each question (9-15), fill in the missing information in the numbered space using a word, numbers or letters.
· After you have listened once, replay the recording.

Invoice number: (9) ______
Invoice date: (10) ______ February 2002
Photocopy paper: (11) ______ boxes, ￡ 9.94 for each
V. A. T. at (12) ______ %
Total to pay: (13) ______
To reach us by:17th March 2002
Contact name: (14) Marjorie ______
Telephone No.:(15) ______

一个实际电源可以等效为（）。

A、一个电动势和内阻的并联

B、一个电动势和内阻的串联

C、一个电动势

D、一节电池