【单选题】这次旅行我欣赏到了美丽的自然风景,( ),我还尝到了当地的风味小吃。
【简答题】求下列集合的并集: (1) A ={ 3,4,6,7 }, B ={ 2,3,5,7 }; (2) A ={ x | x 3 3}, B ={ x |0< x <5}; (3) A={班内全体男生}, B={班内全体女生}.
【简答题】求下列集合的基数. (1)A={0,2,4,6,…,50);(2)B={x|x∈R并且x 2 +1=0}; (3)S={0,3,6,9,…};(4)T={10,11,12,13,…}.
【单选题】The conversion of two syllable nouns into verbs usually involves a change of _____.
【单选题】Narrowing excludes ________.
A.
change from material nouns to common nouns
B.
change from common nouns to proper nouns
C.
words shortened from phrases to retain the meaning of the whole for economy
D.
change from specific meanings to general meanings
【单选题】In English many nouns can be turned into verbs without any change to their form. For instance, the noun walk can be turned into the verb to walk. This phenomenon is known as ______ in morphology.
【单选题】The conversion of two syllable nouns into verbs involves a change of _______.
【简答题】求下列集合的并集: (1)A={x|x 3 3}, B={x|x<-3} ;(2)A={x|x 3 3}, B={x|0