In there compounds, the cyclopentadiene ring has only four hydrogens.在这些化合物里, 环戊二烯环只有4个氢.Those that are aligned perpendicular to the plane are called axial hydrogens.与平面垂直定向的氢叫做直立氢.A methane molecule is composed of one c...
Beautiful butterflies hovered above the wild flowers...美丽的蝴蝶在野花上方飞舞。She hovered on the brink of death for three months as doctors battled to save her...3个月来她一直在死亡线上徘徊，而医生则在全力挽救她的生命。A hawk hovered in the blue sky.一只老鹰在蓝色的...
We subcontracted the work to a small engineering firm.我们把工作转包给了一家小型工程公司。The electrical work have been subcontracted to smith ltd.电气工作已转包给史密斯有限公司.Many cases in the public eye involve contracted or subcontracted detective ...
We classify most male singers as tenors, baritones and basses according to their registers.大部分男歌手根据音域分为男高音 、 中音和男低音.It is necessary initially to classify the headaches into certain types.首先，必须将头痛分为几个类型。We classify editor...