— It was ___________ who helped us out of danger.— What brave and helpful children! We should learn from them.
A:they
B:them
C:their
D:theirs
二元一次方程组 {x+y=213x−2y=8 的解为____
(1.)∠C′EF=32°(2.)∠AEC=116°(3.)∠BGE=64° (4.)∠BFD=116°.