会即时判分、还帮你诊断薄弱点的刷题

先试做几道——选一个答案就即时判分并看到详解。

1. A-level · 数学

   第 1 题. The curve $y = x^3 - 6x^2 + 9x$ has a stationary point at $x = 1$. What is its nature?

   ALocal maximumBLocal minimumCPoint of inflectionDNot a stationary point

2. A-level · 化学

   第 2 题. How many molecules are present in $0.50$ mol of carbon dioxide, $CO_2$? (Avogadro constant $N_A = 6.02 \times 10^{23}\ \mathrm{mol^{-1}}$.)

   A$6.02 \times 10^{23}$B$3.01 \times 10^{23}$C$1.20 \times 10^{24}$D$1.51 \times 10^{23}$