Найнижчий пункт Північної Америки знаходиться нижче рівня океану на 86 метрів(Долина Смерті),а відносна висота між найнижчим і найвищим пунктами-6280м.Обчисліть абсолютну висоту найвищого пункту материка і назвіть його.Назвіть найвищі точки всіх інших материків.

в прямоугольнике ABCd на сторонах AB и Cd отмечены точки M и N так, что AM:MB=1:3, CN:ND=2:5. найдите отношение площадей четырехугольников AMND и MBCN.

24.  When Mr Gabb (come) out of the water, he (find) that somebody (take) all his clothes.25.  After the movie (finish) they (decide) to get something to eat.26.  Many modern medicines were not invented by western scientists but by tribal people who (use) them for gene­rations before Europeans (arrive).27.  It was not surprising that she (start) getting a bad tooth­ache. She (not/go) to the dentist for two years.28.  Her work (look) really neat because she (use) the computer.29.  The chairman's main fault was that he persistently (interrupt) the speakers before they (finish).30. After she (dress) and (eat) her breakfast, Linda (rush) off to her office for a meeting with her accountant.31 Peter already (see) that musical before he (read) the re­view about it.32.  When I (go) into the room I could smell cigarette smoke. Obviously somebody (smoke) in there.33.  Because Jasper (make) an appointment with his dentist beforehand he (hope) he wouldn't have to wait long, although there (be) a lot of people in the waiting-room when he (arrive).34.  By the time Bill (leave) school, he (speak) good French and German. When he (be) at university he (learn) Italian and Spanish.35.  Yesterday Jenny (send) me a very apologetic letter explaining why she (not/do) what she (promise).36.  Ann only (work) there for a few days when she (decide) to leave.37.  The bank (tell) me last week there (be) no money in my account. I (spend) it all.38.  The label (come) off the tin and I didn't know how to cook the meat.39.  When I (get) back after lunch, Jean (tell) me that some­body (phone) when I (be) out.40.  They (get) married in 1990, just a year after they (fall) in love.41.  While I (try) to get my car started, a passing car (stop) and the driver (offer) to help me.42.  Penicillin was discovered when Alexander Fleming (find) some mould growing on a laboratory dish he (leave) be­side the window.43. David (admit) that he (hit) the other car, but (say) he (not/damage) it.44. Jane (miss) the party because no one (inform) her about it.45.  It (turn) out that they (use) that business for quite a time as a screen for their drug-dealing activities.46.  Hardly Harry (start) working when he (realize) that he (need) to go to the library.47.  As Lucy (walk) home, she (try) to remember what (happen).48.  Because Sam and Tony (do) all the work themselves, they (be) unwilling to give the results to John.49.  By the time Liz (be) eighteen she (study) English for six years.50.  Hopi Indians (raise) cotton to make cloth for centuries before the arrival of Europeans in the American Southwest.51.  We (fly) for twenty minutes when the pilot (announce) we (have) to go back because of bad weather.52.  By the time the last marathon runner (cross) the finishing line, nearly everyone (go) home.53.  The house (burn) to the ground by the time the fire brigade (arrive).