I admit that there are quite a few problems, I don't agree that they cannot be solved.
A. Supposing
B. Since
C. While
D. As
网友回答
A. Supposing
B. Since
(答案→)C. While
D. As
解析：句意：尽管我承认有很多问题，但是我认为他们不是不能解决的。A. Supposing假设；B. Since自从、因为；C. While 当……时、尽管；D. As因为、随着、作为。由句意可知选C。
考点: 考查连词的用法。