以下共点力F1、F2、F3的合力可能为零的是( )
A:F1=5N,F2=10N,F3=2N
B:F1=100N,F2=75N,F3=90N
C:F1=11 N,F2=25N,F3=40N
D:F1=31N,F2=7N,F3=50N
读如图漫画“小草的哀求”,漫画所反映的情况可能导致的环境问题主要是( )
—How does he go to school every day?
—He ____ to school every day.