单项选择题
The use of nuclear power has already spread all over the world, However, scientists still have not （1） on what should be done with the large（2） of waste material that tend to increase everyyear . Most waste materials are dealr（3）simply by placing them（4）.But nuclear waste（5）be dealt with very carefully. It gives（6）dangerous radiation and it will continue to be （7）for hundreds, thousands, even mil-lions of years. How should we get rid of such waste material in a（8）that it will not harm the environment? Where can we safely（9）it? One idea is to put this（10）waste inside a （11） container ,（12）is then dropped to the deep bottom of the ocean. But some scientists believe that this way of dealing with nuclear waste could kill fish and other living things in the oceans（13）interfere(干扰)with their growth.. Another way（14）nuclear waste is to send it into space, to the sun,（15）it would be burned. Some scientists suggests suggest that this polluting material（16）buried thousands of meters under the（17）surface. Such under-ground areas must be lree（18）possible earthquakes. Advance id being（19）,But it may still be many years（20）this problem could be finally settled.
12（）
A.that
B.such
C.and
D.which