Due to the fact that both the subject and the topic can occupy the initial position of the sentence, English subject is always deemed as the UNMARKED TOPIC (Lambrecht, 1994), while the topic is not always the subject. In accordance with Rizzi's (1997) topicalization, both the subject and the topicalized constituents can be topics. Many other languages are found to have multiple topics (Erteschik-Shir, 2007). This study agrees that more than one topic is possible in English. With respect to the order, it finds that the "principle of end-weight," applies only to the DP subject topics, but not other preposed constituents. The preverbal constituents in the data abide by the topic-comment structure in general. Via the authentic data, we find that the subject topic is prominently DPs. Non-subject topics are PPs, CPs, adverbs, AdvPs, and DPs, among which PPs are prominent in expository texts while CPs are prevailing in narrative proses. The frequent appearance of the PPs is found to be the genre-effect that PPs are compact structures often used as the sentence opener to make the discourse coherent in expository texts. Meanwhile, the conspicuous occurrence of the CPs, inter alia, the control constructions, is due to the characteristics of the chronological linkage in narrative proses.