how to remove an imported Object background?

[Rez]

Hi
Sorry my English is not good.
I started using power point today .
It is awesome .




I import a musical symbol in my project.
it is a clef and it will be on my horizontal lines.
the problem is when I put it in its position the background of the symbol is covering the lines .
how can I remove the back ground?
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Also I have another question . normally I must to ask my question under the last one or is it better to post in new page ?