Have an aim in life,or your engeries will be all wasted
=If you don't have an aim in life,your engeries will be all wasted.
=Only if you have an aim in life will you make good use of all your engeries
=You will make good use of all your engeries if you have an aim in life
汉语意思：
确立人生的目标,否则你所有的精力/能量都会被浪费.
祝你开心如意!