Give affirmative response to all questions. 1. Tā xiànzài niàn lìshǐ. 他/她现在念历史。 He is studying history now. Tā niàn lìshǐ, niànle duó jiǔ le? 他/她念历史,念了多久了? How long has he studied history? 2. Tā niànguo lìshǐ. 他/她念过历史。 He studied history. Tā niàn lìshǐ, niànle duó jiǔ? 他/她念历史,念了对久? How long did he study history? 3. Tā xiànzài hái niàn lìshǐ. 他/她现在还念历史。 He/she is still studying history. Tā niàn lìshǐ, hái xiǎng niàn duó jiǔ? 他/她念历史,还想念多久? How long does he/she plan to study history? 4. Tā xiànzài niàn Zhōngguo wénxüé. 他/她现在念中国文学。 He/she is now studying Chinese literature. Tā niàn Zhōngguo wénxüé, niànle duó jiǔ le? 他/她念中国文学,念了多久了? How long has he/she been studying Chinese literature? 5. Tā niànguo Zhōngguo wénxüé. 他/她念过中国文学。 He/she has studied Chinese literature. Tā niàn Zhōngguo wénxüé, niànle duó jiǔ? 他/她念中国文学,念了多久? How long did he/she study Chinese literature? 6. Tā ziànzài hái niàn Rìwén. 他/她现在还念日文。 He/she is still studying Japanese. Tā niàn Rìwén, hái xiǎng niàn duó jiǔ? 他/她念日文,还想念多? How long does he/she plan to study Japanese? 7. Tā niànguo Rìwén. 他/她念过日文。 He/she has studied Chinese. Tā niàn Rìwén, niànle duó jiǔ? 他/她念日文,念了多久? How long has he/she been studying Japanese? 8. Tā xüéguo Yīngwén. 他/她学过英文。 He/she has learned English. Tā xüé Yīngwén, xüéle duó jiǔ? 他/她学英文,学了多久? How long has he/she been learning English? 9. Tā xiànzài hái xüé Yīngwén. 他/她现在还学英文。 He/she is still learning English. Tā xüé Yīngwén, hái xiǎng xüé duó jiǔ? 他/她学英文,还想学多久? How long does he/she plan to learn English. 10. Tā xiànzài zài kōngjǖn zuò shì. 他/她现在在空军做事。 He/she now works for the Air Force. Tā zài kōngjǖn zuò shì, zuòle duó jiǔ le? 他/她在空军做事,做了多久了? how long has he/she been working for the Air Force?