题目

Food safety is ________ important, so the government spares no efforts to prevent food pollution.A. strongly                       B. reasonably C. highly                          D. naturally 答案：C如图，AB为相交两圆⊙O1与⊙O的公切线，且O1在⊙O上，大圆⊙O的半径为4，则公切线AB的长的取值范围为 ．