Keep our old friends is more important than make new friends.此句錯誤.原因正如樓主所言,相關(guān)語法點規(guī)定如下：動詞原形構(gòu)成的短語是不能直接充當(dāng)句子的主語或表語的.需要改成動名詞短語或不定式短語,而且前后的...那I understand that communication with others and expression ourselvesis very important也是不對的吧？應(yīng)該寫成：I understand that communicating with others and expressing ourselvesis very important.對么？沒錯。第一個主語用communication/communicating都可以。但是第二個主語用expression ourseves就不對了，只能說成expressing ourselves。