Before revision:  To address this, we propose a new pretraining scheme that is more suitable for extractive question answering . Given a passage with multiple sets of recurring spans, we mask in each set all recurring spans but one, and ask the model to select the correct span in the passage for each masked span.
After revision:  We propose a new pretraining scheme that is more suitable for extractive question answering . Given a passage with multiple sets of recurring spans, we mask in each set all recurring spans but one, and ask the model to select the correct span in the passage for each masked span.