occur的解釋：

　　v.發(fā)生;出現(xiàn);存在;產(chǎn)生

　　第三人稱單數(shù)： occurs

　　現(xiàn)在分詞： occurring

　　過去式： occurred

　　過去分詞： occurred

　　occur的用法例句：

　　1. If these drugs are stopped abruptly then some withdrawal symptoms mayoccur.

　　如果突然停服這些藥，則可能出現(xiàn)一些戒斷癥狀。

　　2. Keep a pad handy to jot down queries as they occur.

　　手邊放一本便箋簿，以便有問題時(shí)隨時(shí)記下。

　　3. Nitrates are chemicals that occur naturally in water and the soil.

　　硝酸鹽是水和土壤中自然存在的化學(xué)物質(zhì)。

　　4. Emergency cooling systems could fail and a reactor meltdown could occur.

　　緊急冷卻系統(tǒng)有可能失靈，核反應(yīng)堆有可能發(fā)生堆芯熔毀。

　　5. Unless you respect other people's religions, horrible mistakes and conflict willoccur.