①分解因式:x2+2x+1=( ).
②若∠ α=40 °,则∠ α的余角是( )度.
(1)(x+1)2;(2)50°
()滤波器的优点有:体积小、工作稳定、无需调试等。
Some social workers _____ after the people in need while others ____ out food to the local people.
A.looked, gave
B.were looking, gave
C.were looking, were giving
D.looked, were giving