28．Kids are often told to remain ______ they are and wait for their parents if they get lost．
| A．what | B．where | C．how | D．Who |
They asked the teacher _______.
| A．when will they have the exam |
| B．when they would have the exam |
| C．when they have the exam |
| D．when would they have the exam |
Ten minutes has been made full _______ of ________ the problem.
| A．using ; studying | B．use ; to study |
| C．to use ; to study | D．use ; studying |
Tom is so lazy that it is the third time that he ______ late this week.
| A．has came | B．is coming | C．came | D．has come |
_______ on the fact, the report should be reliable.
| A．Basing | B．To be base | C．Based | D．To base |
John is a creative person. He can often _____ ideas that are surprising to his classmates.
| A．come across | B．come up to | C．come up with | D．come into |