英语完形The bicycle is one of the simplest yet most useful inven

英语完形
The bicycle is one of the simplest yet most useful inventions in the world.What is most surprising is that it was not _46_ earlier,although the great inventor Leonardo de Vinci had drawn pictures for bicyles and also for flying machines and some other things.Those things were not produced _47_ long after he died
A person roding a bicycle uses _48_ energy to make the bicycle move,and there is no pollution at all when you are riding.Even so,in _49_ counties,most people don′t go to work by bicycle,It isnof because the bicyles are expensive or people feel _50_ if they ride to work.It′s because _51_ cars on the roads becomes larger.It certainly becomes _52_ to ride a bicycle.As a resut,more people put their bicycies away and go to work _53_ their cars and in this way the situatio(情形) is made more seriuous._54_ the best way to make riding safer and more popular is to create pethes(开设通道) only for bicycles,and to make _55_ so diffi-cult and expensive for drivers to take theis cars into the city that they will go back to using their bicycles
46 A invent B inventing C invented D toinvent
47 A before B when C since D until
48 A much B no C little D many
49 A developing B developed C large D small
50 A lucky B glad C sorry D tired
51 A the number ofB a mumber of C this kind ofD allkinds of
52 A safer B more dangerous C cleaner D funnier
53 A by B in C for D at
54 A Hardly B May be C Perhaps D Nearly
55 A it B them C us D that