Question

Helping others is 8 habit，_______you can learn even at an early age.

A.it
B.that
C.what
D.one

Answer 1

【答案】：D
代词that指代可数名词时相当于the one。是特指。而0ne是泛指可数名词单数，相当于a／an+名词单数。本句意为：帮助别人是一种习惯，一种你从小就学到的习惯。0ne后面是省略了that的定语从句，而one在这里又作前面a habit的同位语。