often

由于 have to 与一般的助动词在语法特点上并不完全相同,所以语法学家们把它划为半助动词。它与副词的相对位置,就是与一般助动词的区别之一。副词(often, frequently, usually, apparently 等)应当搁在 have to 之前。例如:

1. We apparently have to go. 很显然我们必须去。

2. People travelling long distances frequently have to decide whether they would prefer to go by land, sea, or air. (New Concept English, Book 3, L. 44) 人们作长途旅行时，往往不得不决定究竟取道陆路、海洋还是航空。

3. In order to follow the buffalo, the Indians often have to move their camps. (DAI) 为了跟随野牛，印第安人常常不得不迁移营地。

位于实义动词之前、助动词或连系动词之后，是 often 等频率副词的最常见位置。为了与前文衔接，可以把 often 放在句首；为了加强 often 的意义份量，也可以把（very）often，（quite）often 放在句末。（参见 always $^{1}$ ，usually）请对比：

1. I often go there. 我常常去那里。

2. Often I did not see Papa until the evening. 我常常直到晚上才能见到爸爸。

3. We go to the countryside very often. 我们常常去农村。