The direction of screw dislocation motion is generally . A.
the direction of crystal slipping B.
perpendicular to dislocation line C.
parallel to dislocation line

单项选择题The Lantern Festival has been the carnival of the Chinese people since ancient times, the reasons are as follows, except ________. A、All the serious Spring Festival rites were over on the Lantern Festival. B、Whether rich or poor, male or female, old or young, people would enjoy the lantern display on the Lantern Festival. C、The emperors, the ministers, and the mass would celebrate together. D、The unmarried girls can get married with their beloved ones.

单项选择题What is to be introduced when people meet for the first time