美国各年龄段独居人口的比例

The response covers all four years and five age groups with a clear overview of rising percentages and the leading 55–64 group. However, it confuses percentages of people with percentages of households and sometimes with population counts. The final comparison would be clearer with explicit growth baselines and the oldest groups’ 2000 values.

Ideas progress logically from a general statement through chronological stages, with cohesive devices such as meanwhile, by 1900 and finally used naturally, despite a slightly confusing reference to the 50 years in the final paragraph.

Vocabulary is flexible and largely precise, including items like proliferation, comparatively, uptick and across the board, though phrases such as proliferation in the number of people for percentage data show occasional imprecision.

A range of structures is used with generally good control, including complex comparisons and relative clauses. Occasional errors include present perfect for the completed historical period, “The 1950”, and the missing closing comma after the inserted age label “17-26”.

The response identifies the overall rise and the consistently highest age group, and reports the endpoints. However, it incorrectly treats the first visible bars for younger groups as proof of when they began living alone, and gives little detail about the contrasting increases by 1950.

Ideas are organised logically by age group with cohesive devices used naturally, giving clear progression throughout the response.

Vocabulary is sufficiently flexible for the task, with apt phrases such as 'followed similar trends' and 'figures for all age groups increased', though range is not extensive.

Sentence structures are varied and mostly accurate, with only minor slips such as subject-verb disagreement in 'the percentage... were highest'.

The response covers the periods and key comparisons with a clear overview and mostly accurate figures. However, it extends the 1850 values to every age group despite only three visible bars, and its overview could distinguish uneven growth and percentages within age groups more clearly.

Ideas progress logically from overview through 1850, 1900 and 1950 to 2000 with effective linking devices such as 'while', 'by 1950' and 'followed by', showing clear progression throughout.

Vocabulary is flexible and precise for describing trends and proportions, including 'minimal', 'cohorts', 'climb' and 'markedly', with only occasional less natural phrasing.

Complex sentences with subordinate clauses and participial phrases are generally accurate. Structures such as “While the figures ... were minimal” and “with the 55-64 group reaching nearly 9%” help combine comparisons without obscuring the meaning.