  The latest work on language representations carefully integrates
contextualized features into language model training, which enables a series of
success especially in various machine reading comprehension and natural
language inference tasks. However, the existing language representation models
including ELMo, GPT and BERT only exploit plain context-sensitive features such
as character or word embeddings. They rarely consider incorporating structured
semantic information which can provide rich semantics for language
representation. To promote natural language understanding, we propose to
incorporate explicit contextual semantics from pre-trained semantic role
labeling, and introduce an improved language representation model,
Semantics-aware BERT (SemBERT), which is capable of explicitly absorbing
contextual semantics over a BERT backbone. SemBERT keeps the convenient
usability of its BERT precursor in a light fine-tuning way without substantial
task-specific modifications. Compared with BERT, semantics-aware BERT is as
simple in concept but more powerful. It obtains new state-of-the-art or
substantially improves results on ten reading comprehension and language
inference tasks.
