good grasp of sth

a good /solid / sound grasp of something (a firm understanding of something) хорошо знать что-л., хорошо разбираться в чем-л., иметь хорошие знания или навыки

A recent study shows that even educated mothers today feel they need a better grasp of basic kitchen techniques as a coping mechanism during the current recession.

get / have a grasp of sth;
give a grasp of sth

see under
[get a fix on]