An ecosystem consists of the living and nonliving things in an area __________ interact(互相作用) with one another.
| A．that | B．where | C．who | D．what |
. ________ they will not come to join us, we have to change our plan.
| A．Seeing that | B．Supposing that | C．For | D．When |
E) Granting that F) Providing that G) Considered that H) While
. There are dirty marks/spots on her trousers ________ she had wiped her hands.
| A．where | B．in which | C．when | D．that |
. You should make it a rule to leave things ________ you can find them again.
| A．so that | B．when | C．where | D．and then E) there |
. He told me to leave out the articles in this sentence ________ it is possible.
| A．where | B．in which | C．that | D．what |
. They were surprised that a child should work out the problem _____ they themselves couldn't.
| A．once | B．then | C．while | D．if |