c and g say the sound in their name (c:see g:jee) if followed by e, i. or y. They are then called "soft c and g." The other sound as in cat and dog, is "hard c and g." 

ce ci cy: centre    success    fence    city    accident    recite    cycle    fancy. 

ge gi gy: gentle    badge    danger    giraffe    agitate    gymnastics    Egypt    energy. 

Exceptions: get    give. 

Where there are two c’s, the sound is like x: success    accident. I explain that In success the c before e says s, but the first c is not any of ce ci cy so it says hard c. In accord there is no ce ci cy, so there is only the k sound.

Where there are two g’s, the sound is j: suggest    exaggerate.