I didn’t quite follow him because he explained the theory _____that is too abstract for me.
--Did a letter come for me? --Yes, ___ came for you this morning.
He is determined to devote himself to ___ the country.
Whenever we were ___, he is always ready to ___ us some help.
The way ___ you are doing it is completely crazy.
The potato is a plant ____ in places ____ it is too cold to grow some other plants.