<prompt> tafadhali geuza maudhui haya ya swahili kwenda kwa kiingereza.katikati liko beseni la ziwa chad lililokuwa kati ya maziwa makubwa kabisa duniani lakini limepungua sana, hasa mwishoni mwa karne ya 20.  <response>: lake chad, one of the worlds largest lakes, has been shrinking dramatically since the end of the 1960s. 