Some problems ___ in the lecture by Mr.Smith are very popular in our school, such as the waste of electricity, water and food, etc...
Have you seen Jack recently? I wonder with his classmates.
We hope that as many people as possible join us for the picnic tomorrow.
When you introduce me to Mr. Johnson, could you please say for me?
—Is there any other student wants to visit Wutai Mountain?
—The problem is very difficult. I'm afraid you can't work it out now. — I fail this time, I will try it again.