44. Using a Doppler ultrasound device, fetal heartbeats can be detected by the twelfth week of pregnancy. 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.
關於這道題的答案c,og的解釋是choice c suggests that physicians can use a doppler ultrasound device after they detect fetal heartbeats.選項c“Detecting fetal heartbeats by the twelfth week of pregnancy, a physician can use a Doppler ultrasound device.”是邏輯主語結構,前面的部分和主句之間有先後關係嗎?我不知道有這種説法,請指點!
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