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Anna comes from Russia. She is 17 years old. She’s going to stay with the Black family for a year. Anna comes to England because she wants to study English. She helps Mrs. Black（1）______________ housework and goes to English (2) _______________ every Wednesday and Friday afternoon.

Anna is now in London. Everything is new to her. She finds life is (3) _______________from that in Moscow. Some things are great in London, but many things are not so nice.  The shops are (4) _____________ in London than those in Moscow. But it’s very expensive to (5) ____________ breakfast in London.

一辆巡逻车最快能在10s内由静止匀加速到最大速度V_m=50m/s，并能保持这个速度匀速行驶，问该巡逻车在平直的高速公路上由静止追上前方2000m处正以V=35m/s的速度匀速行驶的汽车，至少需要多少时间？