硬质合金材料的热导率很大,磨削时不易产生磨削裂纹。( )
参考答案:错
I have many books ,but _____ deals with the problem.
A none of which B none of them C call of which D all of them
女性,1天。出生后腹胀,无排便,如图,诊断为__________________。