as debt-laden students head for degrees they think will maximize their earning potential, many vital courses suffer.

請(qǐng)問(wèn)這句話degrees做先行詞的定語(yǔ)從句，that為何省略，做賓語(yǔ)了嗎？

As debt-laden students head for degrees they think will maximize their earning potential, many vital courses suffer.

they think will maximize their earning potential 這是嵌入式定語(yǔ)從句。定語(yǔ)從句本身是個(gè)主從復(fù)合句，they think是主句，that will maximize their earning potential為賓語(yǔ)從句，關(guān)系代詞that并不在主句中作成分，而是在賓語(yǔ)從句中作主語(yǔ)。關(guān)系詞所在的分句，嵌入到they think這個(gè)分句中作賓語(yǔ)，這種定語(yǔ)從句就叫做嵌入式定語(yǔ)從句 embedded relative clause。關(guān)系代詞在定語(yǔ)從句中作主語(yǔ)一般是不能省略的。但假如關(guān)系代詞在嵌入式定語(yǔ)從句中作賓語(yǔ)從句的主語(yǔ)，則是可以省略的，而且是非常容易見(jiàn)到的。

再給你一個(gè)嵌入式定語(yǔ)從句省略作主語(yǔ)的關(guān)系代詞的例子：

This is the book my teacher says is very useful. book后省略了that。

網(wǎng)友可以在答疑網(wǎng)搜索嵌入式定語(yǔ)從句“。