注意：1). 词数不少于60；

2). 开头已给出，不计入总词数。

    Last month, we went to the exhibition displaying China's outstanding achievements over the past five years.

    A proverb says, “Time is money”. But in my opinion, time is even ____precious than money. Why? Because when money____(be) spent, we can earn ____back. However, when time____(go), it will never return.

    It is known to all that the time we can use is ____(limit). Therefore, we should make use____our time more ____(full) to study hard so as to serve our country in____future. But it is a pity that there are a lot of persons____do not realize the value of time. They spend their precious time smoking, drinking and playing.

    In a word, we should form a good habit of ____(save) time. Do not put off what can be done today till tomorrow.

${\int }_0^1(e^x+2x)dx$等于（    ）