答案：D

题目分析：词义辨析。Strictly speaking严格说来；steadily speaking平静地说；exactly speaking严格说来；roughly speaking大体上说；句意：—有多少人参加了本次展览？—我不敢确定。大体上说来，一千或者更多。故D正确。

点评：Strictly speaking严格说来；steadily speaking平静地说；exactly speaking严格说来；roughly speaking大体上说；都是由不同的副词加上speaking构成的短语，要在上下文语境中加以辨析。