3. 如图,直三棱柱ABC−A1B1C1ABC-A_{1}B_{1}C_{1}ABC−A1B1C1中,底面三角形A1B1C1A_{1}B_{1}C_{1}A1B1C1是正三角形,EEE是BCBCBC中点,则下列叙述正确的是?(?(?( )))