随手拿起一本英语语法书，都可以找到讨论悬垂分词（dangling participle）的章节。分词是从动词变形而来，但功能却是形容词。分词必须搭配其逻辑主语，才完整，否则会产生病句，即所谓的悬垂（dangling）状态。本期的文章，我将把重点放在讨论一个较为常见的悬垂分词，也就是过去分词followed。让我们先来看以下例句：

原句1：Metal precursors were introduced into separate polymer blocks, followed by removal of the templates by pyrolysis.

这里followed的逻辑主语是什么？不论是位置最接近的blocks，还是句子开头的precursors，看起来都不对。实际上，这是个典型的悬垂结构，introduction 作为followed的主语，并没有出现。该句可作以下修改：

改句1：

Introduction of the metal precursors was followed by removal of the templates by pyrolysis.

改句1中，follow的主语被明确写出来，这是修改悬垂结构的方法之一。另一种改法是把用subsequently＋子句，来替换掉分词短语：

改句2：

Metal precursors were introduced into separate polymer blocks, and the templates were subsequently removed by pyrolysis.

以下提供更多参考例句：

原句2：We prepared anhydrous CDCl3 by drying commercial CDCl3 over CaSO4 followed by distillation under nitrogen.

改句：

We prepared anhydrous CDCl3 by drying commercial CDCl3 over CaSO4 and then distilling it under nitrogen.

原句3：Coated coverslips were prepared by adding polymer solution (20 μL) followed by spin-coating.

改句：

Coated coverslips were prepared by the addition of polymer solution (20 μL) and subsequent spin-coating.

原句4：In 1997, continuous monitoring of CO was initiated on the first ship followed by the other two ships in 1998 and 1999, respectively.

改句：

In 1997, continuous monitoring of CO was initiated on the first ship, and CO monitoring on the other two ships began in 1998 and 1999, respectively.

原句5：The catalyst and the activated carbon were mixed in an agate mortar, followed by pelletizing and sieving into 0.15–0.25 mm granules.

改句：

The catalyst and the activated carbon were mixed in an agate mortar, and the mixture was then pelletized and sieved into 0.15–0.25 mm granules.

原句6：The sample was pretreated in 5% O2/He at 500°C for 1 h, followed by cooling down to 150°C.

改句：

The sample was pretreated in 5% O2/He at 500°C for 1 h and then cooled to 150°C.

原句7：Cooperative action of the anion and the metal center promoted ring opening to generate an oxyanion, which then attacked CO2 followed by ring closure to afford the cyclic carbonate.

改句：

Cooperative action of the anion and the metal center promoted ring opening to generate an oxyanion, which then attacked CO2; subsequent ring closure afforded the cyclic carbonate.

Cooperative action of the anion and the metal center promoted ring opening to generate an oxyanion; the oxyanion then attacked CO2, and subsequent ring closure afforded the cyclic carbonate.

原句8：The focal adhesions at the blunt end of the teardrop were retracted, whereas those at the sharp end were extended, followed by nucleus translocation into the neighboring teardrop.

改句：

The focal adhesions at the blunt end of the teardrop were retracted, whereas those at the sharp end were extended; the nucleus was subsequently translocated into the neighboring teardrop.

The focal adhesions at the blunt end of the teardrop were retracted. In contrast, those at the sharp end were extended, and the nucleus was subsequently translocated into the neighboring teardrop.

原句9：The lysates were incubated with MeHg for 30 min at 37°C, followed by reaction with 10 µM BPM for 30 min at 37°C.

改句：

The lysates were incubated with MeHg for 30 min at 37°C and then allowed to react with 10 µM BPM for 30 min at 37°C.