To guarantee safety of old people, it must attend reasonable application of medicines.

为确保老年患者的用药安全，应提高老年人的合理用药水平。

Discontinuous single stroke operation, two hands button start. Emergency stop apparatus is set to guarantee safety.

间断式单次行程操作 、 双手按钮开动,设有紧急停止装置,确保操作安全.

So, in fact, this double blind placebo controlled study does not guarantee safety or efficacy because the test leaves far too many questions unanswered.

所以实际上，双盲对照研究并不会保证疗效和安全，因为它留下太多无法回答的问题。