题目

As more Americans go to mainland China to take jobs，more Chinese and Americans are working side by side. These cross­cultural partnerships，while beneficial in many ways，are also highlighting tensions that expose differences in work experience，pay levels and communication. In the last few years，a growing number of Americans in their 20s and 30s have been heading to China for employment，attracted by its faster­growing economy and lower jobless rate. Their Chinese co­workers are often around the same age.But the two groups were raised differently. The Americans have had more 人在感觉寒冷时，会不由自主地出现“寒战”现象，此反射的效应器是（　　） A、骨骼肌B、立毛肌C、血管平滑肌D、皮肤毛细血管