Question re W3TC expires failing

One thing I can’t seem to resolve with W3TC is YSlow giving my site an “F(0)” for Add Expires headers. It lists “26 static components without a far-future expiration date”. Looking at the 26 they seem to all be things like the three examples listed below. I am thinking this is unavoidable since these might be scripts that are hosted on the other party’s servers, not mine? I don’t fully understand scripting though so if there is a way for me to get the expire dates for these fixed, I would like to know. Thanks!

https://pagead2.googlesyndication.com/pagead/sma8.js

https://www.gravatar.com/avatar.php?gravatar_id=f3bad9bceaf9fa174ffb925b319dfc4e&size=20&default=mm

https://apis.google.com/js/plusone.js