---I always have difficulty in ________new words.----Why not _____ your English teacher for help.
__________he is ill, __________he goes to school.
The story is about Lei Feng.It's very ______.
—Which is______,the sun,the moon or the earth?—Of course,the moon is.
I bought ______ for my son,but ______ for myself.
—______ you in America in 1999?—Yes, I ____________.