Fighting an artificial greenhouse effect seems to be the greatest of environmental challenges, ________？

— Peter, you feed the gold fish and the two little tortoises, ______?　— I did it in the morning; it’s a routine for me now．

 --Look at the photo , is this Gina’s mother?--Yes, _______.

--- What’s this ?   ---         .

It is the first time that Martin has been to the South Pole, ________?