9. a single word can change the meaning of a sentence, a single sentence can change the meaning of a paragraph.
A
Just as
B
Even though
C
Until
D
Unless
just as意为“正如”；even though意为“即使”；until意为“直到”；unless意为“除非”，句意为：正如紧紧一个单词就能改变整句句意一样，仅仅一个句子也能改变整个段落的含义。故选A。
理解句子意思并且选出合适连词。
连词的使用