In China, the education is divided into three _______: basic education, higher education and adult education.
After the flooding,people were suffering in that area,________ urgently needed clean water,medicine and shelter to survive.(2012·江苏,22)
Portia,for ________ physics had once been very hard,turned out to be a physicist.
Gun control is a subject ________ Americans have argued for a long time.
Wind power is an ancient source of energy ________ we may return in the near future.
She showed the visitors around the museum,the construction ________ had taken more than three years.(2011·江西)