大家好 有几个og解释不懂的 求解。

891758149

Unlike the original National Museum of Science and Technology in Italy, where the models are encased in glass or operated only by staff members, the Virtual Leonardo Project, an online version of the museum, encourages visitors to "touch" each exhibit, which thereby activates the animated functions of the piece.
(A) exhibit, which thereby activates
(B) exhibit, in turn an activation of
(C) exhibit, and it will activate
(D) exhibit and thereby activate
(E) exhibit which, as a result, activates

A     Which has no antecedent in the sentence, so it is unclear what activated the display.

这个想问的是which跟在了 exhibit的后面 为什么不是说它错误修饰了exhibit 而是直接说没有先行词？

Affording strategic proximity to the Strait of Gibraltar, Morocco was also of interest to the French throughout the first half of the twentieth century because they assumed that if they did not hold it, their grip on Algeria was always insecure.
(A) if they did not hold it, their grip on Algeria was always insecure
(B) without it their grip on Algeria would never be secure
(C) their grip on Algeria was not ever secure if they did not hold it
(D) without that, they could never be secure about their grip on Algeria
(E) never would their grip on Algeria be secure if they did not hold it

这个想问的是but with/without 这样的用法叫什么 是什么知识点？

谢谢各位啦！