One possible version：
At present, more and more people choose to travel abroad when they have holidays。The reasons are obvious 。above all，with the development of people’s living standard and economy ，they can afford to go abroad 。besides ，more people are becoming interested in foreign cultures，therefore they are eager to visit them in their eyes。
However ，some people behave very badly in foreign countries，for example ，they drop litter everywhere ，as well as spit freely in public ，which not only shows bad personal qualities ，but also does great harm to the image of the country。
It’s well known that China is an ancient civilized country with a long history 。country’s prosperity enables us to travel abroad ，and we should always bear / keep in mind ：it is everyone’s responsibility to uphold image of our motherland。

略

One possible version：
At present, more and more people choose to travel abroad when they have holidays。The reasons are obvious 。above all，with the development of people’s living standard and economy ，they can afford to go abroad 。besides ，more people are becoming interested in foreign cultures，therefore they are eager to visit them in their eyes。
However ，some people behave very badly in foreign countries，for example ，they drop litter everywhere ，as well as spit freely in public ，which not only shows bad personal qualities ，but also does great harm to the image of the country。
It’s well known that China is an ancient civilized country with a long history 。country’s prosperity enables us to travel abroad ，and we should always bear / keep in mind ：it is everyone’s responsibility to uphold image of our motherland。

略