The complete correct analogies would look like this:
1) Wood is to fire as food is to SUBSISTENCE. (Fire needs wood to keep on burning and stay alive, same as a person needs to eat food to survive).
2) Grinning is to cheerful as teetering is to PRECARIOUS. (A person that is cheerful will naturally display a grin; while precarious means to be unbalanced, which would make someone teeter or sway unsteadily and likely fall).
3) Conniving is to scheming as terrible is to ABYSMAL. (Scheming is a stage of planning of some wrong-doing, which would come before the conniving by taking action on that wrongful plan. Here, the word "abysmal" is being used as a worsening of a terrible thing).
4) Mournful is to sad as gluttonous is to VORACIOUS. (To be mournful is to suffer sadness from a loss, so they're natural companions. The same is the case for "voracious" and "gluttonous", for both mean to have an exaggerated apetite).
Hope this helps!
