— Don't you think Professor Johnson's lecture is boring?
— No, not at all.He gave us plenty of examples, and we're deeply ________.
A:surprised
B:embarrassed
C:disappointed
D:impressed
李白在《蜀道难》一诗中,写出了剑阁地势险要,易守难攻的特点的句子是“剑阁峥嵘而崔嵬,____,____。”
先化简,再求值:xx2-1·x-1x-2,其中xx+1=2x+1
生活中处处有化学,下列有关说法正确的是( )