(A) Using a Doppler ultrasound device, fetal heart-beats can be detected by the twelfth week of pregnancy.
(B) Fetal heartbeats can be detected by the twelfth week of pregnancy, using a Doppler ultrasound device.
(C) Detecting fetal heartbeats by the twelfth week of pregnancy, a physician can use a Doppler ultrasound
device.
(D) By the twelfth week of pregnancy, fetal heartbeats can be detected using a Doppler ultrasound device
by a physician.
(E) Using a Doppler ultrasound device, a physician can detect fetal heartbeats by the twelfth week of pregnancy.
答案是E。看到OG對B的解釋:Choice B contains the same main clause and dangling modifier, now at the end.
我想請教大家一個延伸問題

句型: N1+ V+..... N2, Ving/pp....... .
假設不考慮脫節
這樣的句型是否還有雙向修飾的問題?(不知道修飾的是N1還是N2)