I couldn’t work out this problem ________ my teacher helped me.
A. before B. unless C. because D. until
_________ my mother was washing clothes, my father was reading books.
A. While B. When C. Before D. After
When the first ______ came to the US, they were hungry as they have nothing to eat.
A. students B. pioneers C. heroes D.soldiers
Spring is the best _______ of the year, because we can see lots of beautiful flowers.
A. date B. day C. season D. vacation
I ________ the room yesterday, so it is not dirty today.
A. clean B. cleaned
C. will clean D. is cleaning
When the sun shines, the clouds _________ , and we can see everything much better.
A. clear B. clean C. appear D. leave
