At this point esch chromosome consist of a pair of chromatids and the two associated chromosomes are termed a tetrad.此时每条染色体由一对染色单体构成,这两条联合的染色体称为四分体.Microspore abortion occurred after the tetrad formation.小孢子败育发生在四分体形成以后...
Ivins downplays the idea of silver - suited space travelers.艾文斯对[空人银制衣裳]点子并不看好.After a short rest the travelers pushed on towards the coast.旅行者稍稍休息后,继续朝着海岸行进.Numerous travelers head for Elk, and other north coast getaway...
Draw your child's outline with a heavy black marker.用浓黑色的毡笔画出你孩子的轮廓。He placed a marker where the ball had landed.他在球落地的地方放了个标记。Step off twenty feet and then place a marker in the ground.先步测20英尺,再在地上做出标记....
他把那些断片切碎，然后把它们焊在一起。He cuts the pieces and solders them together.这些零件完好地焊在一起了.The parts welded together perfectly.在这样的温度下焊钢需要速度和技术.It takes speed and skill to weld steel at this heat....
If relations between Hanoi and Washington begin to normalise, anything is possible.如果河内和华盛顿之间的关系开始恢复正常，任何事情都有可能。President Mitterrand arrived in Hanoi yesterday to bury old colonial and cold war enmities.密特朗总统昨天到达河内，以期结束长...