a﹣1与3﹣2a是某正数的两个平方根,则实数a的值是( )
A:4
B:
C:2
D:﹣2
—Come on, Susan. You can exercise, learn and so on.
①在BC上找一点P,使点P到AB和AC的距离相等;
②在射线AP上找一点Q,使QB=QC.
—Scientists all over the world are ______ new drugs to treat cancer.
—It will help many sick people.