Mr. Wang came home so thin and weak that his own children hardly______ him.
| A．knew | B．realized | C．recognized | D．noticed |
I have always been honest and straightforward , and it doesn't matter_______I'm talking to.
| A．Who is it | B．who it is | C．it is who | D．it is whom |
We cannot figure out ________ quite a number of insects, birds, and animals are dying out.
| A．that | B．as | C．why | D．When |
Along with the letter was his promise ________ he would visit me this coming Christmas.
| A．which | B．that | C．what | D．whether |
The other day, my brother drove his car down the street at ________ I thought was a dangerous speed.
| A．as | B．which | C．what | D．That |
May and susan are twins and I can’t tell_____is_____.
| A．which ;who | B．which ;which | C．who ;whom | D．whom ;who |