Where is my pencil-box （改为复数形式）改：where are my pencil-boxes?为什么改为复数形式,原来的is要用are pencil-boxes 为什么要加上

Where is my pencil怎么回答Here( ) Where is my pen and pencil?还是Where are my pen and pencil? where ()my pen and my pencil?1,are 2,is is My ruler?—It‘s in the pencil box选一选,is My ruler?—It‘s in the pencil box选一选,A ,When B,Where C ,Why is,new,where,my,pencil,case（?）连词成句 Where is my ____?I want to do my homework.A.clock B.pencil C.key D.card where is my pencil-box?(改为复数形式）where _____ my _____? Where is还是are my pen and my pencil box?有理Where is还是are my pen and my pencil box?有理由更好. my pencil is ____ my pencil case where is your pencil?where is your pencil? No,（） pencil is in the pencil case.A I B my C his D me A：Oh,no!My book 1 in my backpack.Where is 2 B:3 book is on the table.A:OK.My keys.Yes,my keys!Where are 4 keys?B:Your keys are in your backpack,too.A:Yes,yes...Where are my pencils?B:5 under the bed.A：And 6 my pencil case?B:It's on the chair.Oh!N ______!where is my pencil?______,I don t know.A.Sorry ；excuse me B.Hello；OhC.Excuse me；Sorry D.Hi；Er Where are my pencil box () baseball Where _____ my pen and pencil? Where( )the erasers?( )in my pencil case And where's my pencil-case? Where are my pencil?做否定回答