Neverbefore_______sorapidlydevelopingasitistoday．
A、hasourcountrybeen
B、ourcountryhasbeen
C、hasbeenourcountry
D、ourcountryhasn’tbeen
A、氧流量05-1L/min，氧浓度不超过40%
B、氧流量2-4L/min，氧浓度不超过50%
C、氧流量4-6L/min，氧浓度不超过60%
D、以上都不是
Itseemsasifthesun_____roundtheearthsinceitrisesintheeastandsetsinthewest.
A、circles
B、iscircling
C、hasbeencircling
D、werecircling
Whatarethecharacteristicsofgoodwritings?
Thosefamiliarwitheveningdresswillalways______blackwithelegance.
A、link
B、associate
C、connect
D、relate