题目内容：

Do you want to help others—but don’t know where to start? Do you feel that the challenges facing us are too big for one person? One advantage of supporting the American Red Cross is that each of our individual contributions is magnified(放大)when we all join together．Another advantage is that it's easy to start helping．You can start this every minute，by using your mobile to send a text message to make a $10 donation to one of our ongoing campaigns．

Donate to Help Victims of Natural Disasters

Text REDCROSS to 90999 to give $10 to American Red Cross Disaster Relief, which    helps people affected by disasters such as floods，earthquakes．wildfires and hurricanes．

Please consider making a donation today to help the thousands of people who have been    affected by these disasters．

Donate to Help Reduce Deaths from Measles(麻疹)

Text PREVENT to 90999 to give $ 10 to the Red Cross and help us vaccinate（注射疫苗）    children against measles．

Started in 2001．the Measles & Rubella Initiative—led by the American Red Cross，    provides technical and financial support to governments and communities for mass vaccination    campaigns around the world．The Initiative has supported the vaccination of more than 1 billion children helping to reduce measles deaths by 78％globally(compared to 2000)．

Please consider making a donation today to help us continue this campaign．To learn more，visit www．Measlesrubellainitiative．org．

Important Information for Text Donors

You can make a $ 10 donation to the American Red Cross．Charges will appear on your    wireless bill．All purchases must be authorized by account holder．You must be over 18 years old or have parental permission to participate．Text STOP to 90999 to STOP．Text HELP to 90999 for HELP．

1.The text mainly aims to tell us__________________．

A．how to keep our wireless bill safe when making donation

B．how to make a $10 donation by text message

C．when to become an authorized account holder

D．how to make individual contributions magnified

2.We should text_______to 90999 if we want to help victims of natural disasters．

A．STOP     B．PREVENT    C．HELP   D．REDCROSS

3.What does“this campaign”in Paragraph 6 refer to?

A．Offering help to the disaster victims．

B．Supporting the American Red Cross．

C．Mass vaccination around the world．

D．Applying for charges on wireless bills．

4.1f a school boy wants to be a text donor, he should _____________.

A．get the permission of his parents

B．reach the marriage age

C．pay ＄10 to own an account

D．stop his daily purchases