I live in a city where jobs are difficult to get and finding well—paid jobs is even1 . Many people have to walk a long way to work 2 they can't even afford an old, used car.

    Yesterday I 3one of these people when I was driving home. A man was walking down the road and trying to ask for a 4 from the passing cars. Two cars in front of me passed him by. 5wanted to do the same but the sight of that poor man remained in my mind for quite a moment. 6 I drove back and gave him a ride.

    As I drove along, we had a conversation and I 7 that the man was trying all his best to support his 8 while working a temporary(临时的)job. Every coin he had was going to 9 the house and food.

    But as we came close to the house he was living in, I saw his tired eyes grow 10. His little girl was playing in the front yard and 11 into her daddy's arms as soon as he was out of the 12 . I was almost lost in that happy moment. I smiled, said 13 to them and wished them future happiness. Then I 14.

    That day, the journey home which used to seem so 15 became very short.

公元前2500年左右的亚非文明代表有古代中国文明、古代印度文明、古代埃及文明、古代巴比伦文明，孕育这四大文明的相同地理因素是(   )

椭圆$\frac{x^2}{16}+\frac{y^2}{9}=1$的焦距为（　　）