He didn’t understand French, so I offered to _____ forhim.

The experiment shows that proper amounts of exercise,if _____ regularly, can improve our health.

The shoes were worn out, what’s more, they aren’tworth _____.

The subway __________in our city, and I’m sure there will be fewer traffic jams in the future

Smiles around the world _____ be false,______ other feelings like anger, fear or worry.