I have _____eraser _____my pencil case.
A:a; in
B:a; at
C:an; in
D:an; at
-- Who is your English teacher, Helen?
-- __________ is.
下列既能跟盐酸反应,又能跟氢氧化钠溶液反应的物质是①Al2O3 ②MgO ③NaHCO3 ④Al(OH)3