Term-base-related issue: Is there a way to open a source text and its (already translated) target text into SDL Trados, considering that the source and target texts are saved separately in MS Word or as PDFs?

My client has asked me to create a term base with all his past translations (made by another translator) and has no bilingual file – only separate source and target texts. Do I have no choice but to copy each sentence of the target text and paste it into the corresponding segment in SDL Trados? This would be very time consuming and I was wondering if there was a quicker way that would make the whole process cheaper for my client.