12.He is always ________and never feels tired.
The governments are _____ to improve the employment and medical situation of the citizens.
Kevin was not good at Chinese at first. After two months in China, _____, he made great progress.
The worst tornado of all time occurred in 1925, ______ three US states.
______ right in the center of the city, the park attracts a lot of tourists.
Physics ________ my favorite subject. I like it so much that I wish we had a physics class every day.