过敏症状的增多部分是由于环境内分泌干扰物的危害。
参考答案：对
一辆汽车运一堆货物，运走了总数的35%，这时剩下的比运走的还多18吨。原来这堆货物有多少吨？
Mr. Smith works as a government official now, but he ____________ in a middle school for 5 years.
A．has worked
B．worked
C．had worked
D．had been working
