pencil box 如果改成复数的话,在哪个单词后加s,一般像这样的两个名词变复数有什么规律么?

pencil box 如果改成复数的话,在哪个单词后加s,一般像这样的两个名词变复数有什么规律么? It isn't his pencil-box?改成复数 radio ,pencil box,的复数 pencil-box的复数形式是什么? It's a pencil box 复数改 英语复数形式apple.box.pencil.class.baby.pencil 英语句子单数变复数1、Is that her English book?(改成复数)2、Those aren't Chinese buses.(改成单数)3、It isn't his pencil-box?(改成复数) Is's a pencil-box.改为复数句 It is a red pencil box.变成复数形式. This is his pencil-box.改为复数句子怎么改? that is her pencil—box(改复数句) 按照句子后的要求改变句子7、Is that her English book?(改成复数) 8、Those aren't new buses.(改成单数) 9、It isn't his pencil-box?(改成复数) is that a box改成复数 There be句型变复数地点状语要不要变比如说There is a pencil in that box.转为复数要不要把box→boxes>?如果必须选择一个呢?请说明理由. 合成名词girl student复数形式是girl stedents,那为什么pencil box的复数形式是pencil boxes? 把Where is his pencil.改成复数句 The lunch box is his.(改成复数句） pencil box英文意思