英文解釈

Readers may be interested to learn that the sign in the front of the cinema has been illuminated for the first time in 15 years showing that audiences can look forward to the hugely popular musical Ruby Ruby.

15 yearsの後にカンマなどなく、いきなりshowing that...と来ることに違和感があるのですが、この文はit'sなどが省略されているのでしょうか？
例：...15 years, it's showing that...