Hello, I'm Tom. I'm ____ and ____. I do exercise every morning. I run for 30 ____. I ____ eat vegetables and fruit. I don't eat too much meat. Because it's ____ for me. I work hard at school and at sports. Sometimes I help my parents at home.
东北地区的城市主要集中在 ( )
“神舟6号”太空舱利用NiFe2O4将航天员呼出的CO2转化为O2，而NiFe2O4的质量和化学性质都不变，则NiFe2O4在该过程中（ ）
现在有一种叫“固体清新剂”的商品，把它放置在厕所、汽车、饭店内，能有效的清新空气、预防感冒等，“固体清新剂”发生的物态变化是（ ）
(Mg2+) = 0.15mol/L，c(Cl-) = 0.2mol/L，则c(NO3-)为（ ）