A Review on the Role of Token Frequency in the Acquisition of Argument Structures

The role of frequency in second language acquisition has become an important focus among second language acquisition researchers. Argument structure, as one of the core topics of verbs, has always been the focus of academic attention. Frequency has a certain influence on second language construction acquisition, and the corresponding research is abundant. This paper reviews the research on the acquisition of argument structure construction with token frequency and its enlightenment to teaching, and puts forward some suggestions for future research

The Review and Prospect of the Acquisition and Teaching Methods of Phrasal Verbs

The phrasal verb (PV) plays an important role in the English output, but the English learners’ acquisition and usage situation of PVs is not so optimistic. Thus, phrasal verb has always been the hot research topic for the recent years. The previous researches mainly include the current English learners’ usage situation or the avoidance of the phrasal verbs, the factors affecting the acquisition of the phrasal verbs like the social and subjective factors and the linguistic rules, and the different teaching methods of phrasal verbs like the different input and output ways and the combination of input and output ways. All of these aspects are deserved to be studied and concluded to find out more effective methods for phrasal verbs acquisition and teaching. And the combination of cognitive linguistic method and the task-based output method maybe deserved to be tested for the potential advantages of both ways and the research gap

Chlorine and Bromine Isotope Fractionation of Halogenated Organic Pollutants on Gas Chromatography Columns

Compound-specific chlorine/bromine isotope analysis (CSIA-Cl/Br) has become a useful approach for degradation pathway investigation and source appointment of halogenated organic pollutants (HOPs). CSIA-Cl/Br is usually conducted by gas chromatography-mass spectrometry (GC-MS), which could be negatively impacted by chlorine and bromine isotope fractionation of HOPs on GC columns. In this study, 31 organochlorines and 4 organobromines were systematically investigated in terms of Cl/Br isotope fractionation on GC columns using GC-double focus magnetic-sector high resolution MS (GC-DFS-HRMS). On-column chlorine/bromine isotope fractionation behaviors of the HOPs were explored, presenting various isotope fractionation modes and extents. Twenty-nine HOPs exhibited inverse isotope fractionation, and only polychlorinated biphenyl-138 (PCB-138) and PCB-153 presented normal isotope fractionation. And no observable isotope fractionation was found for the rest four HOPs, i.e., PCB-101, 1,2,3,7,8-pentachlorodibenzofuran, PCB-180 and 2,3,7,8-tetrachlorodibenzofuran. The isotope fractionation extents of different HOPs varied from below the observable threshold (0.50%) to 7.31% (PCB-18). The mechanisms of the on-column chlorine/bromine isotope fractionation were tentatively interpreted with the Craig-Gordon model and a modified two-film model. Inverse isotope effects and normal isotope effects might contribute to the total isotope effects together and thus determine the isotope fractionation directions and extents. Proposals derived from the main results of this study for CSIA-Cl/Br research were provided for improving the precision and accuracy of CSIA-Cl/Br results. The findings of this study will shed light on the development of CSIA-Cl/Br methods using GC-MS techniques, and help to implement the research using CSIA-Cl/Br to investigate the environmental behaviors and pollution sources of HOPs.Comment: 30 pages, 5 figure