In August 1977, a satellite to gather data about the 10 million black holes which are thought to be in the Milky Way.
A、launched
B、waslaunched
C、hasbeenlaunched
D、islaunched
Many other new techniques are now available that enable more research___ (do) in the test tube to see if chemicals produce harmful biological effects.
Youmayusebike________yougiveitbacktometomorrowmorning
A、unless
B、provided
C、though
D、because
The fixed star was a planet.（）
A、madeof
B、madefrom
C、madeupfor
D、mistakenfor
Whenapersonimmigratestoanothercountry,heshould_(conscious)adapthimselftothenewenvironment