The federal Environmental Protection Agency has determined that DEET, when used as directed, is safe.联邦环境保护机构已经认定,DEET, 当在指导下使用是安全的.DEET and other chemicals that against insects can keep mosquitoes from biting.避蚊胺和其他能驱赶昆...
沸腾钢在铸锭前不脱氧或轻度脱氧.In the case of rimming steel, no or some deoxidation is carried out before casting.由于废弃的部分小,沸腾钢的成材率较高.With small portion to be scrapped rimming steel has a high yield of good steel....
the abolition of serfdom in Russia in 18611861年农奴制在俄国的废除Islanders have campaigned for the abolition of one of the three tiers of municipal power on the island.岛上居民发起一场运动,要求废除岛上三级市政管理层中的一级。Abolition of children's fac...