A、Because they could get some food. B、Because they are friendly. C、Because they need company. D、Because they want to be protecte

I am an American student learning Chinese in Shanghai. During my study here, my classmates and I often travel around, sometimes beyond the country. Last year, we went to Australia, as we were invited by our Australian friends we made here at the University. In Sidney, it seems that birds are the closest friends of human beings outside the cats and dogs. Especially during the summer season, you may encounter a variety of birds. In a local park where my friends and I barbecued, we enjoyed company of sacred ibis, the white-bodied, black-headed large birds with a long, slightly crooked beak. They would stay very close to us or other BBQers, waiting for any food that might be tossed toward them. When we walk in streets, white parrots or colorful parakeets often fly above our heads from one tree branch to the other. Very frequently you may hear a baby or babies crying somewhere. The cry in fact came from overhead when I first looked around for a crying baby. The sound was made by black crows. You may also see white spotted crows in the street looking for food. If they are truly crows, then the Chinese saying "all the crows in the world are black" has an exception in Australia.
Question No. 15 What is the speaker doing in Shanghai?
Question No. 16 According to the talk, which of the following are NOT the closest friends of human beings?
Question No. 17 For what reason do the birds come very close to people who are having barbeques?
Question No. 18 What bird would make the sound of a crying baby?