Question

完型填空 急！！！

The london underground，or ① it is commonly known，also is called the Tube。It has the distinction of being the oldest ② most complex underground system ③ the world。④ the first half of the 19th century，train services to London were developed。⑤，most trains into London only went to the distant boundary of the city ⑥ building railway tracks into the city⑦ havecaused damage⑧many historic building。

Answer 1

Answer 2

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