【简答题】将下列命题符号化,并指出其真值 . (1) 2.5 是自然数 . (2) 2 与 5 都是素数 . (3) 3 不是偶数或 4 不是偶数 . (4) 只有今天是星期一,则明天才是星期二 . (5) 2+2=4 的充要条件是 3+3=6.
【简答题】complete the following sentences with the words or phrases in the following , change the form if necessary. in charge cut in contribute justify nonetheless He tried to ___...
【简答题】Fill in the blanks with the proper words in their correct forms according to the Chinese meaning of each sentence. Testify justify verify certify 他作证说他没有看见那次事故。 1. He ____that he had not seen the a...
【简答题】Task 3 Complete the following sentences with the words or phrases in the bracket. Change the form if necessary. (in charge cut in contribute justify nonetheless) 1. It was cold. ____...
【单选题】Tom tried to justify his absence from the meeting by ________ that he had been ill that day.
【简答题】Task 3 Complete the following sentences with the words or phrases in the box. Change the form if necessary. in charge cut in contribute justify nonetheless 1. It was cold. ___...
【简答题】下表为人和一些动物的发声频率范围和听觉频率范围,参照表格回答: 发声频率范围(Hz) 听觉频率范围(Hz) 发声频率范围(Hz) 听觉频率范围(Hz) 人 85~1100 20~20000 蝙蝠 10000~120000 1000~120000 狗 452~1800 15~50000 海豚 7000~12000 150~150000 猫 760~1500 60~65000 (1)从上表中你可以知道...