1 . Fluency and ________（准确）are two factors which determine the success of the students learning a second language in the future. (根据汉语意思单词拼写)

2 . Video games can be fun and exciting, but we need to look out when this pastime becomes a(n) ________（上瘾）. (根据汉语意思单词拼写)

3 . Coronaviruses can cause a range of s________ varying from common cold to more serious respiratory（呼吸的）illnesses. (根据首字母单词拼写)

4 . Some people make the______(假设)that English can be improved within a short time, which contradicts the basic principle of language acquisition. (根据汉语提示单词拼写)