In order to ensure smooth and clear transitions between points, you can use '______'.
A.in addition
B.in my opinion
C.in this section I shall discuss x
D.Both B and C

A.A.in
B.in
C.in
D.Both

【参考答案】

A
解析：第四段的第四句列举了起承接作用的词语，A选项就在具中。