a. tell the strangers our personal information.
b. obey the local traffic rules.
c. never stretch our hands out of the window when taking a bus.
d. avoid eating raw and cold food.
e. swim in the dangerous area
A:b,c,d
B:a,d,e
C:a,b,c
用下面的字组词。
电 ____ ____ ____
如图,在△ABC中,∠BAC=90°,PA⊥面ABC,AB=AC,D是BC的中点,则图中直角三角形的个数是____