题干
The April 10, 2010 air crash, with a Russian Tu-145 plane _______ Poland’s president Lech Kaczinsky, his wife and many Polish government and military officials, shocked the whole world.
A：carried
B：being carried
C：carrying
D：to carry
答案(点此获取答案解析）
C
，电场的场强方向平行于三角形所在的平面。已知
、 
和20V。则该电场的场强大小为
