There is a mixture of people from different cultures and ethnic groups in a country. Why? Is this a positive or negative development?

温室气体的增多加剧了温室效应。

One problem with ostrich farming in Britain is____.

Some visitors are interested in other countries' cultures and traditions. How they learn other cultures and traditions? Why this is interesting to some visitors but not to others?

你完全不用刻意去想气质这件事。因为气质就是你自己，你所经历，你所学，你所想的。它就在那里，你想也没有用。