Such occasions are rare _______ the customers complain about the service provided by us.
A. that B. what C. where D. when
_______ makes the books so important is ______ they appeal to readers of all ages, they create a special literary bond between parents and children.
A. As; because B. It; that
C. What; that because D. That; what
This golden opportunity _____ your full attention although ________ to seize.
A. worthy of; is hard B. worth; being hard
C. is worthy; it hard D. is worth; hard
Nowadays, there arises growing concern over the issue of tainted vaccine(被感染的疫苗) ________ around China.
A. swept B. sweeping
C. to sweep D. having swept
WeChat(微信), first released in 2011, provides great paying convenience for the users _________ a text and voice messaging communication service.
A. rather than B. on account of
C. in addition to D. as a consequence of
---Where is Peter? I can’t find him anywhere.
----He went to the library after breakfast and __________ his essay there ever since.
A. has been writing B. had written
C. wrote D. is writing
