take on= gain, aquire take smthg for granted means you dont appreciate smthg's or smbdy's value. "He took it for granted that he would pass the test, but it was harder than he thought"

"Take something for granted" means to not realize how special something is in your life. It's often said retrospectively, after this something is lost. "After we divorced, my life became less bright. I didn't how realize how happy she made me, even when we were mad at each other. I guess I really took her for granted." "Take on" usually means to assume a false aspect of ones identity or to reveal one's true identity. It is often used in a context of slight deception. "After it was found out that the Russian President had once been in love with the American president, the war took on a whole new meaning." "They spy, in order to not be notice, took on a different appearance/took on a whole new identity."