When the competition ____ (start), David was still making his way to school.
It's snowing and I can't_____ out to play. （ ）
设三棱柱ABC﹣A1B1C1的体积为V，P、Q分别是侧棱AA1、CC1上的点，且PA=QC1，则四棱锥B﹣APQC的体积为（ ）
=75-30
=45
