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Hi there, can anybody check my homework please?

It's all about tenses.

The words in the round brackets are my answers. Thanks a lot.

Social networking sites(do not seem) to help people make close friends, according to researchers who studied how the websites (are changing) friendships.

Although social networking (means) that many people now (are having) hundreds or even thousands of friends, the researchers (are believing) that to become a real friend, it is still important to actually meet up.

Social networking (has become) very popular recently, but although people now (keep in touch) with more friends online, the researchers found that we still usually have only around five close friends.

We only develop real friendships when we (know) we can trust someone.