Autism (儿童自闭症) is a serious mental illness, especially of children, in which one becomes unable to communicate or form. relationships with others. There has been alarming rise in autism rates in the U. S. and 【S1】______ some other developed nations recently, which have come one of the most 【S2】______
A.
【参考答案】
been ∧ alarming →an been ∧ alarming →an 解析：冠词缺漏。此处rise是一......