问题补充:
Some languages, Russian and German,are not easy to learn.
A. for example
B. such as
C. as
D. that is
答案:
A. for example
(答案→)B. such as
C. as
D. that is
解析:这句话是说,一些语言,如俄罗斯语,德语是不容易学习的. for example是举例说明, such as列举事例,as 做“象”讲的时候,是连词,that is也就是说,不符合句意,选B