Answer:
1. correct
2. correct
3. Ich habe viel gearbeitet. (D, not C)
The past participle gearbeitet should be placed at the end.
4. Ich habe in der Bibliothek gelernt. (C, not B)
The past participle of the verb <em>lernen</em> is gelernt. You need to add the prefix ge- and the suffix -t to the verb root because it is a weak, or regular, verb. (The verb <em>lernen</em> consists of the root <em>lern</em>- and the infinitive ending -<em>en</em>.)
5. Wir haben sie natürlich gelesen. (A, not B)
<em>Lesen</em> is a strong, or irregular, verb, so its past participle form is also irregular: gelesen.
6. correct
7. Wir haben "Herr der Ringe" gesehen. (D, not B)
<em>Sehen</em> is a strong, or irregular, verb, so its past participle form is also irregular: gesehen.
8. Ich habe ihm eine neue Uhr geschenkt. (A, not C)
The past participle of the verb <em>schenken</em> is geschenkt. You need to add the prefix ge- and the suffix -t to the verb root because it is a weak, or regular, verb. (The verb <em>schenken</em> consists of the root <em>schenk</em>- and the infinitive ending -<em>en</em>.)
