乙烯和氯气加成得到的产物是大分子。
紫外线硫化氢分析仪可以分析出低浓度的()。 ["H2S硫化氢","H2S硫化氢、COS羰基硫","MeSH甲基硫醇","H2S硫化氢、COS羰基硫、MeSH甲基硫醇"]
下颌骨下方中央至后囟顶部的距离() ["双顶径","枕额径","枕下前囟径","枕颏径","双颞径"]
FR矫治器的唇挡截面呈泪滴形,其下缘应在牙龈上方至少() ["A.7.5mm","B.6mm","C.8.5mm","D.7mm","E.8mm"]
出口横径() ["9cm","10cm","11cm","11.5cm","12.75cm"]
何谓单车试验?制动装置单车试验的项目有哪些?