I feel doubtful about his ability to do the work.
我怀疑他有无做这件事的能力。

It is doubtful whether he will be able to come.
他能否来还很难说。

to be doubtful about something
对某事有怀疑

The important thing to note in this entry is that the debit is made to the Allowance for Doubtful Accounts and not to the Uncollectible Accounts.
需要注意的是借记方是坏账准备账户而非坏账损失账户。

Private Sector Division allowance for doubtful accounts receivable
私营部门司的应收帐款呆帐备抵额

According to these reasons, the accuracy of the analyzed results seems to be doubtful.
由于这些理由, 上述方法计算成果的精度值得怀疑。

The insecticidal action must be considered doubtful.
这个杀虫作用是值得怀疑得。

But it is doubtful whether additional quantitative easing would add much to this.
但令人质疑的是，更多的定量宽松是否会带来更大帮助。

One case of a doubtful allergy on an adult Holstein cow with gentamycin
成年荷斯坦牛对庆大霉素疑似过敏一例

could that have affected her memory? Uh, it's doubtful.
会不会影响她的记忆?不好说

The fittings seem doubtful, and Jian head and case might be matched afterwards.
装具好像有问题, 剑首, 剑格可能是后配的。

People might use the knowledge of your wifes doubtful birth against you, and against your children, too.
人们会用你妻子不明不白的出生来攻击你以及你的子女。

Your comment that their party will readily agree is rather doubtful.
你方所称他们会欣然同意，这一点值得怀疑。

The remaining nasal intrinsic muscles are of doubtful importance in nasal airway patency.
其余鼻内肌群在保持鼻气道通畅方面可能会有一些作用。

I am doubtful whether he is still alive.
我怀疑他是否还活着。

Im doubtful whether shes still alive.
我怀疑她是否还健在。

I am doubtful whether she is still alive.
我难以确定她是否还活着。

I am doubtful whether the author is still alive.
我怀疑该作者是否还活着。

A doubtful allergy case of a Holstein cow with atropine
荷斯坦牛疑似阿托品过敏一例

Whether the authorities will allow inspection is highly doubtful.
当局是否允许检查还是个大问号。

allowance for bad and doubtful debts
坏账及呆账备抵

My being doubtful alone will bring me a harvest of curses.
我这一怀疑肯定要遭人骂的。

It was followed by big names like America Online, Microsoft and Netscape before sites with more doubtful content began to kick in.
紧随其后的著名网站有美国在线、微软和网景，再接下来就是一些内容可疑的网站了。

We eyed each other amicably if doubtfully.
我们彼此用一种怀疑的，但却友好的眼光看待对方。

Doubtful Points on Emending of Ancient Books of Yunnan.
疑义相与析