On 5th Octoter, I bought one of your expensive“Apollo”fountain pens from Julian’s(朱利安公司)，a big department store of this town．Unfortunately，I have been unable to use the pen because it leaks(漏墨水)．I am very disappointed with my purchase．On the advice of Julian’s manager I am returning the pen to you.

Please arrange for the pen to be fixed or replace it with a new one and send it to me as soon as possible.

There are many countries in the world where the water supply is not sufficient for the growing population, and other sources have to be found. Even the sea is used in some countries, but the problem of removing the salt is a severe one. Sea water can be used for a supply of drinkable water if it can be separated from the salt dissolved in it.

The program aimed at creating a single, federated sign-on system is called ______.

Cars are responsible for most of the smog in cities，______(这已经对环境造成了严重的污染)．

He rushed (danger) __ across the street to catch the bus.

Exposure to all media is important because they all contribute materials for ______.