【正确答案】 C

【答案解析】[理由] (A)so that+主语+助动词(如：may、can、will等)+V
以便……(此为连接词，不置句首，应置于主句后)
[例] You should work hard so that you can pass the test.
=You should work hard in order that you can pass the test.
(你应当用功，这样的话才能通过考试。)
(B)except that… 只可惜……(此亦为连接词，多置于主句后)
[例] John is nice except that sometimes he may lose his temper.
(约翰人不错，只可惜有时候会发脾气。)
(C)now that… 既然……(此亦为连接词，多置于主句前)
=since...
[例] Now that you're here, I can tell you the truth.
=Since you're here, I can tell you the truth.
(既然你在这儿，我可以跟你说实话。)
(D) with that 有了那个(不是连接词)
由于空格后有主语you及现在完成时动词have finished(已经完成)，得知空格内应置入连接词，故不可选(D)。根据语意及用法，(C)应为正选。