题干
— Mike, where is Mr. Li?
—He _______a speech on Chinese art to the first-year students in the hall.
A：gives
B：gave
C：has given
D：is giving
答案(点此获取答案解析）
D
CH3OH(g) + H2O(g) ΔH ＝－49.0 kJ•mol－1。一定条件下，向体积为1 L的密闭容器中充入1 mol CO2和3 mol H2，测得CO2和CH3OH(g)的浓度随时间变化曲线如右图所示。下列叙述中，正确的是 ( )
