The trouble with such resources as coal, oil and gas ______ that they are not renewable.
| A．was | B．are | C．have been | D．is |
_________, I always feel I want a few more days.
| A．However long is a vacation | B．However long a vacation is |
| C．However is a vacation long | D．However a vacation is long |
--- Bake is intelligent and experienced.
--- That is ________ his advantages lie in applying the post.
| A．what | B．how | C．where | D．why |
During _________ 3-day conference, global warming became _________ major concern of all the representatives.
| A．the; a | B．a; the | C．the; \ | D．a; \ |
Not until _______ home _______ her appointment with the doctor.
| A．she arrived; did she remember | B．did she arrive; that she remember |
| C．she arrived; when she remembered | D．did she arrive; had she remembered |
By nine o’clock, all the Olympic torch bearers had reached the top of Mount Qomolangma, _________ appeared a rare rainbow soon.
| A．of which | B．on which | C．from which | D．above which |