为了消除鸦片,林则徐进行了____。
______ earthquake happened on ______ morning of April 14th in Yushu, Qinghai. By far, over 2,000 people have died.
“每人前进一小步,社会前进一大步。”这句公益广告语告诉人们( )
①C1M∥AC;
②BD1⊥AC;
③BC1与AC的所成角为60°;
④B1A1、C1M、BN三条直线交于一点.