静电疗法治疗疾病的原理是利用（）
A.静电作用
B.静电场作用
C.交流电作用
D.交流电场作用
E.电磁波作用
参考答案：B
把下列的数字按正确的顺序写在横线上。
six, five, thirteen, seven, four, fifteen, fourteen,
eight, twelve, three, two, nine, ten, one, eleven
_____________________________________________
Color TV was first shown in 1929. It took more than two decades, ________， until 1951, for
color broadcasts to begin in the USA.
A. though B. therefore C. otherwise D. anyway
