You will get lost easily you take a map of the city with you.
A:until
B:unless
C:although
D:if
直角三角形两锐角的平分线所夹的钝角的度数为( )
①2个氢原子____②5个水分子____③地壳中含量最多的金属元素是____
④2Fe3+ 前面“2”表示____,右上角“3”表示____.