Fossil records indicate______existing in the past have become extinct.A．that many species

Compared to alternative energy, one of the disadvantages of fossil fuels is ______.A．Minin

According to the conversation, the use of fossil fuels ______.A．should be banned in order

The second paragraph focuses on the fact that ______.A．fossil energy was once very cheapB．

【C14】______A．liveB．deadC．workingD．recording

Scientists use observation and experimentation to examine a specific concept ______ existi

_________(54)A.recorders B.antennasC.cameras D.se