The fact has worried many scientists ______ the earth is becoming warmer and warmer these years.

A． what

B． which

C． that

D． though

[单选题]______ has become a fact of modem life, with millions of people now shopping on-line.A．E-mailB．E-commerceC．E-learningD．E-communicationA．B．C．D．

[单选题]Scientists have many theories about how the universe ___ into being.A． cameB. was comingC． had comeD. would come

[单选题]Many scientists have been probing psychological problems.A．solvingB．exploringC．settlingD．handling

[单选题] （75） has become a fact of modern life, with millions of people now shopping on-line.（75）A． E-mailB． E-commerceC． E-learningD． E-communication

[单选题]D．o scientists know how many cryptic species exist?A．Not yet.B．Yes, they do.C．They will know the answer in another one or two years.D．They will never know the answer.

[试题]7.In spite of many risks, scientists will finally［A］anenvironmentwithoutultravioletlight［B］alotofhomes［C］anEarthlikeenvironment［D］anenvironmentwithatmosphere

[单选题]Many scientists _____their own eyes and ears than the theories of the ancie

[单选题]［A］ As more has become known of the many thousands of African plant species and their complex ecology, naming, classification, and mapping have also become more particular, stressing what was actually present rather than postulating about climatic po

[单选题]［A］ As more has become known of the many thousands of African plant species and their complex ecology, naming, classification, and mapping have also become more particular, stressing what was actually present rather than postulating about climatic po

[单选题]［A］ As more has become known of the many thousands of African plant species and their complex ecology, naming, classification, and mapping have also become more particular, stressing what was actually present rather than postulating about climatic po