20.（ ）

(单选题)—Hi, Maria, you look tired.—I am tired. I ______ on my homew (单选题)Who do you think will ______ since the president has resigne (单选题)There are three main classes of drugs, ______ has a differen (单选题)______ I went to the seaside, I picked up a great many shell (单选题)— Wang Ming is clever but does not work hard at his lesson.— (单选题)Intergenerational transmission happens between ______. (单选题)Boa Sr is most likely to be ______. (单选题)What is the passage mainly about？ (单选题)Which of the following places is named after a person? (单选题)What does the underlined phrase “die hard” in Paragraph 1 pr