In English conditional sentences, the condition clause (protasis) is a dependent clause, most commonly introduced by the conjunction if. Other conjunctions or equivalent expressions may also be used, such as unless (meaning if...not), provided (that) , providing (that) and as long as.irst conditional or conditional I refers to a pattern used in predictive conditional sentences, i.e. those that concern consequences of a probable future event (see Types of conditional sentence).
Lesson Summary [edit]. 1  Mechanical weathering breaks existing rock into smaller pieces without changing the composition of the rock. 2  Ice wedging and abrasion are two important processes of mechanical weathering. 3  The main agents of mechanical weathering are moving water, wind, glacial ice and gravity.
Once the rock has been weakened and broken up by weathering it is ready for erosion. Erosion happens when rocks and sediments are picked up and moved to another place by ice, water, wind or gravity. Mechanical weathering physically breaks up rock. One example is called frost action or frost shattering.