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had undergone is the most popular phrase on the web.

had underwent 140,800 results on the web	had undergone 17,740,000 results on the web More popular!
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It doesn't look like this phrase is very popular! The search could not find any examples on the internet.	In the empirical therapy study patients had received chemotherapy for malignancy or had undergone hematopoietic stem affected children, the elderly, patients with eye disease who had undergone seven (27, 75%) had undergone a nephrectomy. cell transplantation (including 39 allogeneic transplantations). Since the times of emperor Augustus the Roman Empire had undergone many changes. Freddie Mac had undergone a similar probe concerning improper accounting procedures before the investigation of Fannie Mae. They found to their surprise the features had undergone no observable shift. Twenty

had underwent

140,800 results on the web

had undergone

17,740,000 results on the web

More popular!

It doesn't look like this phrase is very popular! The search could not find any examples on the internet.

In the empirical therapy study patients had received chemotherapy for malignancy or had undergone hematopoietic stem
affected children, the elderly, patients with eye disease who had undergone
seven (27, 75%) had undergone a nephrectomy.
cell transplantation (including 39 allogeneic transplantations).
Since the times of emperor Augustus the Roman Empire had undergone many changes.
Freddie Mac had undergone a similar probe concerning improper accounting procedures before the investigation of Fannie Mae.
They found to their surprise the features had undergone no observable shift.
Twenty