At present, no widely approved vaccine exists for malaria.
目前没有被广泛认可的疟疾疫苗。

2.mandatory 强制的

The offence carries a mandatory life sentence.
这种罪行依照法律要判无期徒刑。

3.stipulation 规定

Clifford's only stipulation is that his clients obey his advice.
克里弗德惟一的规定是他的客户必须听从自己的建议。

4.infection 感染

The doctor probed the wound for signs of infection.
医生检查伤口是否有感染的迹象。