Question

Although everything seems to have been taken into consideration，       accident can happen when the astronauts walk in            space．

A．不填；the

B．an；the

C．the；the

D．an；不填

Answer 1

D

考查冠词的用法，第一空是泛指，所以用不定冠词a，第二空考查space前不加冠词，这类词还有nature,society,所以选D。