1£® The elderly patients still prefer the traditional way, ______ online booking system is supposed to be convenient and fast.

A. while                       B. though                            C. unless                      D. as

2£®Rare species in the world, ______ by hundreds every year, must be jointly preserved by all countries, or humans will encounter ecological disaster in the near future.

  A. disappeared     B. disappearing     C. disappear           D.having disappeared