Temporal perception is crucial for Large Language Models(LLMs) to effectively understand the world. However, current benchmarks primarily focus on temporal reasoning, falling short in understanding the temporal characteristics involving temporal perception, particularly in understanding temporal relativity. In this paper, we introduce TempBench, a comprehensive benchmark designed to evaluate the temporal-relative ability of LLMs. TempBench encompasses 4 distinct scenarios: Physiology, Psychology, Cognition and Mixture. We conduct an extensive experiments on GPT-4, a series of Llama and other popular LLMs. The experiment results demonstrate a significant performance gap between LLMs and humans in temporal-relative capability. Furthermore, the error types of temporal-relative ability in LLMs are proposed to thoroughly analyze the impact of multiple aspects and emphasize the associated challenges. We anticipate that TempBench will drive further advancements in enhancing the temporal-perceiving capabilities of L

As a crucial step in extractive document summarization, learning cross-sentence relations has been explored by a plethora of approaches. An intuitive way is to put them in the graph-based neural network, which has a more complex structure for capturing inter-sentence relationships. In this paper, we present a heterogeneous graph-based neural network for extractive summarization (HETERSUMGRAPH), which contains semantic nodes of different granularity levels apart from sentences. These additional nodes act as the intermediary between sentences and enrich the cross-sentence relations. Besides, our graph structure is flexible in natural extension from a single-document setting to multi-document via introducing document nodes. To our knowledge, we are the first one to introduce different types of nodes into graph-based neural networks for extractive document summarization and perform a comprehensive qualitative analysis to investigate their benefits. The code will be released on Github.