【简答题】若cosα≠0,sinα+3cosα+1=0,则tanα=( ). (A)3/4 . (B)4/3 . (C)-3/4 . (D)-4/3 .
【简答题】氨基酸分子中氨基和羧基的数目相等时,氨基酸显 性;氨基的数目比羧基的数目大是,氨基酸显 性;氨基的数目比羧基的数目小时,氨基酸显 。性。
【单选题】If I had , I’dvisit Europe , stopping at all the small interesting places .
A.
. a long enoughholiday
B.
. an enough long holiday
C.
. a holiday enough long
D.
. along holiday enough
【单选题】一般而言,证券投资风险是指对投资者()的背离。
【单选题】--I'm leaving for Europe on business next Saturday. --___________
【单选题】为合理利用资源,配制砂浆时应尽量选用( )水泥和砌筑水泥。
【单选题】--I'm leaving for Europe on business next Saturday.--______.