---Why was it ______ you were so angry？
---Because we failed to take part in the basketball match.
A. which B. that C. how D. when
The Bakers intend to buy a house but _____ must be within their power.
A.they B.one C.it D.which
Fully ______in preparing teaching assignment at school，she no longer has much time to enjoy the various activities as usual.
A. occupy B. occupying
C. occupied D. to occupy
---Where is your report of this month？
---Oh sorry，I______ to email to you.
A. forget B. have forgotten
C. forgot D. was forgetting
She is always the first staff to go to the office and the last to leave，______ I guess is why she is promoted so quickly.
A. who B. which C.that D.what
EBOLA（埃博拉） is said_______ another big health challenge to our humans over the past several months .
A. becoming B. to become
C.having become D. to have become
