All around the world，an increasing number of people are spending their time taking part in online volunteering projects.What encourages them to help strangers without expectation of money or even thanks?

　　Radha Taralekar helped teach Imelda how to protect herself from HIV，though the two have never met，and neither knows the other's name.Taralekar received no payment for the job.For Taralekar，the project gave her the chance to use her professional experience."I want to serve people with my medical knowledge，" she said.For some，the inspiration to volunteer online is far more personal.After losing his wife to cancer，Tony Selman spent many hours online helping Cancer Research to collect information on the illness."Seeing how painful she was when my wife was dying，I decided to help scientists find a way to treat cancer，" he said.

　　Interests and hobbies are also one of the reasons.Sam Luk joined other online volunteers to try to help the police solve murder cases.The police posted them online，calling for volunteers to help them to make sense of the messages."I am interested in this and I love Sherlock Holmes，" said Luk.

　　For writer Clay Shirky，some large online volunteering projects help millions of people，giving him a sense of achievement.He helps write Wikipedia，the world's biggest encyclopedia(百科全书)，which is written by people willing to use their professional knowledge.

阅读短文，判断正(T)误(F)

1．We can know that Radha Taralekar may be a doctor.(T)

2．Tony Selman decided to help Cancer Research because his wife died of cancer.(T)

3．Sam Luk volunteered to help the police because of his duty of work.(F)

4．There are four reasons why people help strangers online mentioned in the text.(T)