天然砂可分为河砂、海砂和山砂,()比较洁净而实用。

集料的定义

He's been _______ on the phone all morning.

A. talking
B. talked

I've_______ playing this game for hours now.

A. being
B. been

My dad_______ been feeling well for a few days.

A. hasn't
B. haven't

They've_______ studying since 10 o'clock.

A. been
B. being

We_______ been living here for very long.

A. haven't
B. hasn't

The dog's been_______ for half an hour.

A. barked
B. barking

( )是指合同订立前、订立时及在合同有效期内,要求当事人实事求是、尽自己所知、毫无保留地向对方所作的口头或书面陈述。

A. 告知
B. 保证
C. 弃权与禁止发言
D. 默示

以下( )不属于保险人的告知内容。

A. 保险标的危险显著增加的情况
B. 保险费交纳的时间
C. 免责条款
D. 保险期限