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
