Later, these rocks proved that ___ in the distant past the Antarctic was covered by plants.
The H7N9 flu is reported ______ higher fever and coughing for several days.
— I'm leaving tomorrow.— Oh, what a pity! I won't be able to see you off. I ____ a tele-conference the whole morning.
On June 16, 2012, it arrested the world’s attention ______ Shenzhou 9 spacecraft was successfully sent into the sky with the first Chinese woman astronaut.
New traffic rules that took effect on January l, 2013 are much stricter______ than in the past.
Rock climbing is ___ great fun. You will get close to ____ nature and take adventures at the same time.