According to entomologists, single locusts are quiet creatures, but when locusts are placed with others of their species, they become excited, change color, vibrate, and even hum.

A: when locusts are placed with others of their species,

B: when placing them with others of their species, then

C: locusts, when placed with others of their species,

D: placing them with others of their species,

E: placed with others of their species, then

對照幾位版友的答案應該是A，不過我想請教一下諸位nn，A裡面的 "locusts are"是否可以省略，感覺很累贅哩...

thanks!!

where does e wrong? "they " have no reference?

who can help?

如果只看句子的結構（先不看修飾句），這句的結構是

Single locusts are quiet creatures, but (when...) they become

excited... brabrabra

E選項，結構變成

Single locusts are quiet creatures, but (placed...) then they

become excited... brabrabra

1. 這裡的then企圖連接主句與修飾句之間的關係，但這樣的連接是沒有必要

的。

2. 過去分詞固然可以作為狀語從句修飾主句主語，但個人認為這裡應加上

when, while, if, after，其關係會比較清楚。

我感觉locusts are 可以省，其主语还是后面句子的主语they。

同意做成时间壮语比较好。