Jules Verne · 1828
Heavy going at CET-4 level. Not unreadable — just not readable the look-every-word-up way.
Coverage = the share of words in the text you already know. The research gives two lines: 98% before independent fluent reading is realistic, 95% for the instructional level that needs support (Hu & Nation, 2000). Proper nouns are not counted as unknown — recognising that it is a name is enough; this book has 400 of them.
Advanced — read it with glosses. 85,753 words in total; at 150 words a minute for a non-native reader, about 9 h 32 min to finish. Average sentence length 15.9 words. Reaching 95% coverage on this book (the floor for readability) takes roughly 22,000 word families.
The opening of A Journey to the Centre of the Earth, word for word. Tap any word you don't know and its meaning here appears beside it — no sign-up, tap as often as you like.
Looking back to all that has occurred to me since that eventful day, I am scarcely able to believe in the reality of my adventures. They were truly so wonderful that even now I am bewildered when I think of them.
My uncle was a German, having married my mother's sister, an Englishwoman. Being very much attached to his fatherless nephew, he invited me to study under him in his home in the fatherland. This home was in a large town, and my uncle a professor of philosophy, chemistry, geology, mineralogy, and many other ologies.
One day, after passing some hours in the laboratory--my uncle being absent at the time--I suddenly felt the necessity of renovating the tissues--<i>i.e.</i>, I was hungry, and was about to rouse up our old French cook, when my uncle, Professor Von Hardwigg, suddenly opened the street door, and came rushing upstairs.
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These are already built, and closest in difficulty to A Journey to the Centre of the Earth.
Ordered by unknown words per 100. Lower reads easier; to step up a level, pick a higher number.
Computed by Readii from the public-domain text (updated 2026-10-21), not estimated by hand. The Readii reading level is our own scale, anchored on unknown-word density; it is not the same system as Lexile or AR and does not convert directly. Unknown words are measured against the CET-4 ∪ Gaokao lists, so this is difficulty for a Chinese-speaking learner, not a native-child reading level.