a) than / is / other / Paris / dirtier / cities / European? {input: Is Paris dirtier than other European countries}?
b) some / small / of / the / are / towns / not / boring / very. {input: Some of the small towns are not very boring}.
c) were/we/walking/the/was/main/along/street/and/which/evening/crowded/that/noisy. {input: That evening we were walking along the main street which was crowded and noisy}.
d) was /an /ancient /there /opposite /church /the /railway /modern /station. {input: There was an ancient church opposite the modern railway station}.
e) uncomfortable /the /where /we /first /was /flat /lived /extremely. {input: The first flat where we lived was extremely uncomfortable}.
f) never /I /have /stayed /the /quieter /in /one /that /town /than. {input: I have never stayed in the quieter town than that one}.
g) the /which / is /the /city /safest /in /world? {input: Which is the safest city in the world}?
h) wide /the /streets / Paris /of /are /empty /never. {input: The wide streets of Paris are never empty}.