在直角三角形中,斜边与较小直角边的和,差分别为8,2,则较长直角边长为( ).
4
-You’re dropped __________ “s” in the word “across”.
-Oh, you are right, __________ letter “s” should be doubled like this “cross”.
A.a, a
B.an, a
C.an, the
D.the, a
简述语言的社会性。