The serious problem ____ mankind now is how to protect the environment effectively.A.faces B.facing C.is faced with D.to face

The ______(照顾) of the old is a serious problem. the large population problem is still serious in china the population problem has become more serious in developing countries. increasing serious problem,air _However serious a problem_ you may have,you should gather your courage to face the challenge.A.However a serious problem B.What a serious problemC.However serious a problem D.What serious a problem 请帮帮看错哪了 the problem will become more serious in the future. before the ___(close) of the factory ,noise pollution was always a serious problem. The food children eat while watching TV makes the problem more serious.的中文. 根据首字母填空：Pollution is a serious problem in major cities t___ the world. the guinness book of world records hunger is a very serious problem in many places whatever后只能加名词吗?可以加how serious the problem all of u ask me the same question that really a serious problem 英语翻译翻译：the population problem has become more serious in developing countries. Another serious problem for environmentalist is the type of tree and forest planted. ___you may have,you should gather your courage to face the challenge.A however a serious problemB what a serious problemC however serious a problemD what serious a problem 英语口语 话题是 what is the most serious problem in the world ? why do you think so?what can we doto solve the problem? you may have,you should gather your courage to face the challenge.A.However a serious problem B.What a serious problemC.However serious a problem D.What serious a problem选C请解释一下however+形容词或副词+主谓的吗如however hot the wea 1.Air p_____is a serious problem in the world now.2.People will have m____free time in the future