Fill in each of the blanks in the following sentences with a suitable preposition or adverb .
1 . Learning a foreign language is___no means an easy task, but requires long-term effort .
2 . If you buy our products__large quantities, you will get better prices .
3 . All students and staff are expected to participate___the ceremony .
4 . The doctors did not want to play___the seriousness of the disease, so they told the patient the truth .
5 . He bought some cheap shoes that fell___after only a couple of weeks .
6 . All flights have been delayed or canceled because___bad weather .
7 . Many modern festivals can be traced back___an ancient legend .
8. We had a great time in the park___the fact that it rained.